Tsumeb Minerals are Amazing, like this Smithsonite – Click here and find amazing photos<\/p><\/div>\n
Small-scale mining continued until 1900, when larger industrial development of the deposit began thanks to a new railroad connecting then quite remote Tsumeb to the coast from which ore could be transported to distant refineries. Initial production had to be hauled over 500 km. to Swakopmund, making it economically unfavorable. After SWA became a German colony, a corporation called the Otavi Minen-Und-Eisenbahngesellschaft, or OMEG was formed, which quickly removed the remains of the famous \u2018green hill\u2019, expanded it into a modest open-pit mine, and soon went underground, chasing higher and higher grades as the pipe-like orebody continued vertically down. After Namibian independence from Germany, OMEG merged into the Tsumeb Corporation, controlled at various times by Newmont Mining and other large global mining consortiums. The deposit, while not especially large on a global scale, had a unique set of mining challenges including its steeply-dipping pipe-like form and the constant danger of flooding, due to extensive paleo-karst systems housing a large aquifer. High grades (averaging 10% Pb, 4.3% Cu, 3.5% Zn, 100 ppm Ag, 50 ppm Ge), made the tremendous expenditure associated with both dewatering the mine and treating the metallurgically-complex ores profitable (Lombaard et al, 1986). When the great Tsumeb mine closed in 1996 and was allowed to flood, over $5 billion in copper, lead, zinc, silver, germanium, and gold had been produced. An effort by a consortium of mineral collectors and dealers led by Ian Bruce was made in the late 1990\u2019s to re-open part of the Tsumeb mine for mineral specimen mining, but unfortunately this was found to be uneconomic.<\/p>\n
Geologically, Tsumeb is part of a small group of high-grade polymetallic, carbonate-hosted \u2018ore pipe\u2019 deposits. Mineralization is confined to dolomitic carbonate rocks of the upper Otavi formation, which is part of large supracrustal sequence overlying Precambrian gneiss and granite in northern Namibia (Guilbert & Park 2007). Mineralization occurs in a pipe-like, steeply dipping cylindrical body bounded by \u2018psuedoaplite\u2019 dikes, which are probably clastic dikes related to complex salt tectonics and salt diapirism which has been observed elsewhere in this sequence in Namibia and neighboring countries. Karst-dissolution, breccias, collapse structures, and faulting are common, indicating mineralizing fluids were probably fairly robust over an extended period. Ore grades are highly variable, but along intersections between favorable lithology and structure, massive sulfide lenses containing up to 60%(!) combined Cu, Pb, Zn, Ag & Ge were commonly found (Guilbert & Park 2007). The great wealth of collectible minerals at Tsumeb is mainly due to the great depths of oxidation and supergene enrichment of primary sulfide ores, with supergene mineralization predominating above 400 meters depth, and considerable secondary mineralization persisting to depths of 800 meters! This great oxidation depth is probably related to the permeability of the dolomitic carbonate rocks, as well as the unique influence of salt tectonics on mineralization. The unusually chemically-diverse hydrothermal fluids associated with mineralization also introduced many unusual metals such as Ge, Ga, Sb, & As, contributing to the huge list of mineral species found at Tsumeb.<\/p>\n
Ask any mineral collector which species he or she first thinks of when the word \u2018Tsumeb\u2019 in mentioned, and the answer will invariably be \u2018azurite.\u2019 Not only did Tsumeb produce azurite crystals of outstanding color and luster, the size was world-class as well, with specimens such as the \u2018Newmont Azurite\u2019 which features crystals to over 20 cm(!). Azurite occurs in a variety of forms, from blocky to tabular to elongate prismatic crystals. Malachite psuedomorphs after azurite are a specialty, with faithfully-preserved sharp green crystals to 10+ cm. being fairly common and occurring in spectacular large groups. Associated minerals include smithsonite, calcite, duftite, olivenite, mottramite, and more, leading to combinations with outstanding colors and aesthetics. Dioptase is probably a close second in terms of beauty and fame from Tsumeb, with the most famous and sought-after specimens consisting of rich \u2018carpets\u2019 of brilliant blue-green crystals to 2+ cm. on a matrix of snow-white dolomite or calcite. Thousands of such specimens were found in the 1960-70\u2019s, but are now quite scarce (or expensive) on the collector market.
\nCerussite is another mineral which reaches its worldwide zenith at Tsumeb, occurring in a variety of forms and colors, from complexly-crystallized, reticulated \u2018snowflake\u2019 crystal groups (sometimes to 30+ cm!) to heart-shaped twins in beautiful limpid shades of yellow to clear. Individual crystals have been reported up to 60 cm(!), surely a record for the species. Inclusions can cause cerussite crystals from Tsumeb to appear green, blue or red, and the luster is typically high. Mimetite, one of the most common secondary minerals in both major oxidation zones at Tsumeb, also reaches a zenith here, with the most famous crystals being from the 1971 \u2018gem pocket\u2019 which produced gem-clear yellow crystals to 6 cm., with only a few dozen good specimens being found. A good mimetite from this pocket would today easily set you back several tens of thousands of dollars. <\/p>\n
No article on Tsumeb would be complete without mentioning smithsonite, which also probably sets a global standard at Tsumeb. Perhaps most remarkable about Tsumeb smithsonite is the variation in color, spanning colorless to yellow to pink to green to deep-blue, and seemingly every shade between. Tsumeb is also one of the few localities in which smithsonite forms well-developed crystals, often to several cm. each and with outstanding luster. As far as rarer species, it is futile to try and cover the breadth and uniqueness of rare minerals from Tsumeb. Species such as cuproadamite, alamosite, arsentsumebite, bayldonite, leadhillite, ludlockite, and olivenite demonstrate that rare does not always mean ugly. While Tsumeb as a mine is probably closed forever, the good news for collectors is that the veritable flood of specimens during the 20th century means that the average collector should be able to obtain good Tsumeb specimens for many years to come. <\/p>\n
Famous \u2018Newmont\u2019 Azurite; Tsumeb Mine- approximately 30 cm. across with crystals to 15 cm. (photo \u00a9 American Museum of Natural History)<\/p><\/div>\n
5.) Kola Peninsula, Russia<\/strong><\/p>\n
Workings of the Umbozero Mine, Khibiny Massif: K. Dembicz photo\/\u00a9 Spirifer Minerals 2009<\/p><\/div>\n
Locality number 5 risks taking us back into the realm of \u2018ugly and rare\u2019 after letting our imaginations roam the colorful crystalline landscape of Tsumeb. But wait! Have you seen the starburst-like sprays of golden astrophyllite crystals in a snow-white matrix? The gemmy, sword-like natrolite crystals to 30 cm? The delicate pink tugtupite, hackmanite, and ussingite whose neon expanses hide dozens of minerals known nowhere else in the world? The Kola Peninsula, extending into the Arctic region of northwestern Russia to the east of the Scandinavian Peninsula, is truly a world-class mineral locality and geological treasure house. While I am deviating somewhat from the \u2018single locality model\u2019 in including the Kola Peninsula (an almost 100,000 square kilometer area), I think this inclusion is justified in that the main mineralized areas, the Khibiny and Lovovero Massifs, are in fairly close proximity to each other, and show strong geological, temporal, and mineralogical similarities. <\/p>\n
The Kola Peninsula (taken here to include to massifs of Khibiny & Lovozero) were long shrouded in mystery to western collectors and mineralogists, and for many still conjure images of distant snow-covered slopes and small \u2018rocks\u2019 with arrows on them. Part of this mystery is political, as the region is in a remote part of what was up until 1994 the Soviet Union, and the strategic nature of the mineral deposits at Kola as well as Cold War tensions limited communication with outsiders about the treasures of the region. Inside Russia (and the USSR), however, is a rich history of geologic exploration at Kola. While native peoples of the Inuit culture made Kola home for thousands of years and surely took note of the unusual appearance of many of the rocks there, \u2018modern\u2019 exploration began in earnest in the 1920\u2019s with the discovery of massive deposits of magmatic apatite at Lovozero (Pekov 2000). Since the USSR had limited ability to import outside resources and did not have large known \u2018conventional\u2019 phosphate ores, the rather unusual initiative was taken to begin mining these apatite ores for their phosphorous content, a critical ingredient in the \u2018state farm collective\u2019 program of industrial agriculture.<\/p>\n
\u2018Stars\u2019 of Lamprophyllite in Nepheline, Umbozero Mine: K. Dembicz photo\/\u00a9 Spirifer Minerals 2009<\/p><\/div>\n
In the 1930\u2019s, as the apatite mines were developed, leading Soviet mineralogist and geochemist Alexander Fersman visited the area and took note of the mineral eudialyte, a complex silicate enriched in Zr and REE\u2019s. Loparite, another complex REE species, was discovered in 1934, and soon an outpost of the USSR Academy of sciences was established at Khibiny (Pekov 2000). Loparite generated much interest both to scientists and the government, as it was a potentially-economic ore of the strategic metal niobium, as well as other rare metals. In fact, much of the development of the rare metal industry in the USSR was shrouded in secrecy, even to those involved in it. Exploration and mining in Kola ceased temporarily during WWII, when many of the mills and mining operations were converted in munitions plants and military equipment factories. Mining and exploration resumed after 1945, but this period leading up to Stalin\u2019s death was somewhat of a dark period for Kola, as most labor at the mines was in the form of \u2018gulag\u2019 prisoners, many there for political reasons. Nonetheless, scientific inquiry into the unique geology of the region continued, with the publication of \u2018Petrology of the Lovozero Massif\u2019 in 1972 by Bussen & Sahkarov marking a research milestone (Pekov 2000). <\/p>\n
Exploitation of both apatite and rare metal ores continued at a fairly steady pace through the early 1990\u2019s, when democratization of the country and the fall of the USSR brought a slowdown in heavy industry, which has continued until today is some areas. Research on the peninsula, however, continued to be strong, with many papers and significant discoveries by scientists such as A.P. Khomyakov, I. Pevok, P. Kartashov, and others. Apatite mining at the Kirovskii mine on the Khibiny Massif and several locations on Lovozero continues today, but unfortunately many rare metal operations such as the famed loparite deposit at Umbozero have fallen in disrepair. Hopefully, with economic strengthening of Russia and renewed global interest in rare metals, particularly the largely-untapped eudialyte ores, mining will return full-force to the region, and with it new mineralogical treasures to be found. <\/p>\n
The great Russian mineralogist A.P. Khomyakov in his laboratory in Khibiny in 1992, with list of possible new minerals behind him (photo \u00a9 O.T. Ljostad\/mindat.org)<\/p><\/div>\n
Geologically, Khibiny and Lovozero are quite complex, but can be explain most simply as a pair of complex multiphase alkalic igneous intrusions of Devonian age, each with a surface expression of ~600 km2, which have intruded the Archean crystalline rocks of the Baltic Shield (Pekov 2000). The intrusions are in deep graben-like structures, likely related to syn-intrusive rifting, and are partly filled with middle Paleozoic age volcanic and volcanoclastic rocks. The main rock types in the massifs are nepheline syenites and related silica-undersatured, nepheline and sodalite-normative alkaline igneous rocks, but there is also a complex suite of mafic rocks ranging from trachyte to phonolite to gabbro, an important piece of evidence in the interpretation that alkalic intrusions often have genetic links to primitive mantle-derived mafic magmas in intraplate settings (Pekov 2000). Enrichment in phosphorous of one of these magmatic pulses led to the development of an immiscible, possibly late-stage melt from which large quantities of primary magmatic apatite were about to crystallize (Pekov 2000). The diversity and rarity of the rock types encountered at Lovozero and Khibiny indeed led to a whole new nomenclature for such rocks- urtites, lujavrites, foyaite, riscchorites and malignites are all important and rare alkalic rocks at Kola. The multiphase and chemically-variable nature of the intrusions created spectacular layering and zonation, both vertically and in cross-section, of different rock types. Both intrusions included eruptive phases and concordantly shallow intrusive units showing spectacular poikilitic (sieve-like mineral intergrowth) textures and evidence of subsolidus crystallization (Pekov 2000). With subsolidus (below the normal melting curve of that mineral assemblage) crystallization came widespread metasomatic alteration, in which one element is removed and replaced by a different element, typically by hydrothermal fluids. Metasomatism and related pegmatite formation are undoubtedly the main factors in establishing the incredible mineralogical diversity of Khibiny & Kola. Pegmatites are abundant in numerous rock types of both massifs, and while often small (a large pegmatite might be ~20 x 1.5 m), they can contain an amazing abundance of minerals: one pegmatite encountered underground in the Umbozero loparite mine contained over 80 minerals! Finally, the sub-Arctic setting of the massifs and lack of appreciable vegetation combined with extensive glacier scouring and erosion means that exposure is generally excellent, and many new pegmatites and mineral localities are discovered each field season. <\/p>\n
Loparite-(Ce) twins of matrix to 1 cm: Khibiny. (photo \u00a9 B. Kantor\/mindat.org)<\/p><\/div>\n
Mineralogically, 507(!) different mineral species have been reported from Khibiny, and 376 from Lovozero. Truthfully, both massifs include dozens of individual localities, but they generally share such strong genetic and chemical characteristics that for the sake of discussion they will be referred to as a single locality here. Starting on the aesthetic end of the mineral spectrum, many collectors will be surprised to learn that both Khibiny and Lovozero have produced spectacular, beautiful crystallized specimens of numerous minerals. Perhaps best-known is astrophyllite, a complex Na-Ti silicate which occurs as golden sprays of radiating crystals to 10+ cm in snow-white matrix. Eudialyte, a rare species which is sometimes a rock forming mineral(!) at both massifs, rarely occurs as sharp, bright pink to red crystals to 5+ cm. Natrolite, a common mineral both in the more evolved rock units and the pegmatite\u2019s of Kola, occurs as sprays of gemmy, sharp clear crystals up to an impressive 30 cm. Loparite, the important ore of Nb & REE\u2019s, occurs as sharp black cubic crystals to several cm, sometimes in attractive interpenetration twins. Neptunite and Lorenzenite, two chemically-different but somewhat similar looking minerals, occur in attractive dark red to black crystals up to the size of a finger. Elpidite, the rare Be silicate, occurs as large hand-sized sprays of radiating white crystals. Kovdorskite, a rare Mg phosphate from the Kovdor apatite mine, occurs as beautiful clear crystals to several cm. The rare fluoride Villiaumite (NaF) rarely occurs as euhedral crystals, but forms attractive \u2018nests\u2019 of bright red cubic cleavages to 20+ cm in some pegmatites.
\nIn terms of \u2018rare\u2019 species (rare being a relative term at Kola), there are hundreds of minerals, and a monograph could (and has) been written on them. Suffice it to say that most occur as attractive crystals <1 cm., while others are only massive, but many, massive or otherwise, have beautiful color and texture, which renders them desirable collection specimens nonetheless. Pegmatite such as the Shkatulka pegmatite in the Umbozero Mine and the pegmatites of Kukisvumchorr Mountain at Khibiny are world-renowned for their complexity. Many are beautiful even to the lay-person, presenting coarse-grained intergrowths of red eudialyte, green amazonite, giant microcline and nepheline crystals, chlakovite, ussingite, and tuptupite and delicates shades of crimson and pink, and smaller \u2018nests\u2019 of vibrantly colored REE and rare metal-bearing minerals. Given that most of these pegmatite\u2019s were discovered as surface outcrops and have never been mined, the treasures of Khibiny & Lovozero should be accessible for generations of mineralogists to come.\n\n\n
\n6.) Illinois-Kentucky Fluorspar District, USA<\/strong><\/p>\nGalena on Fluorite: Denton Mine, Harris Creek Sub-District, Hardin Co. Illinois (photo \u00a9 MIM Museum, Beirut)<\/p><\/div>\n
In light of many of the preceding localities such Mont Saint Hilaire and Tsumeb whose world-class status is indisputable, I was a little hesitant to include the Illinois-Kentucky Fluorspar District in the Midwestern USA to the \u2018top ten\u2019 list, but as much as I tried to ignore it, it kept coming back into my mind. While certainly not as diverse as Mont Saint Hilaire or unique as Tsumeb, the fluorite mines of Southern Illinois and northern Kentucky constitute one of the earth\u2019s premier endowments in beautiful, crystallized mineral specimens. During their operation from the early 19th century up until 1996, literally tens of thousands of fine specimens of fluorite, calcite, sphalerite, galena, witherite, and more were saved, and there is scarcely a serious mineral collector in the world who does not own a specimen from the district. Combine this abundance of specimens with a seemingly endless variety in color and form in this (albeit limited) species list and you have the makings of a world-class locality.<\/p>\n
Fluorite: Minerva #1 Mine, Cave-in-Rock, Illinois- 7 cm. across (photo \u00a9 James Elliot\/FMI: now in the MIM Museum, Beirut)<\/p><\/div>\n
The history of mining and minerals from the Illinois-Kentucky fluorspar district is closely linked to the history of the Midwestern US and the westward migration of pioneers and prospectors in the 18th and 19th centuries. In the early 19th century, Southern Illinois was still a fairly wild and undeveloped region, with local Indian tribes outnumbering white settlers. This changed as word of rich outcropping of galena ore (associated with then less-valuable fluorite) were found along the banks of the Ohio river near what is now Cave-in-Rock, and prospectors as well as farmers began settling the area. Mining in the 19th century focused mainly on galena\/sphalerite Pb-Zn ores, and it was not until a steelmaking process in the 1880\u2019s required fluorite for flux that mining in the district shifted to the massive fluorite (or \u2018fluorspar\u2019) deposits (Goldstein 1997). Before WWII, most mining was focused on the Rosiclare area, but this moved to Cave-in-Rock in later years, with large underground mines such as the Minerva #1, Denton, and Annabel-Lee accounting for most of the fluorite production in the later 20th century. Goldstein (1997) noted over 95 individual mines in the Illinois side of the district, and over 130 on the Kentucky side, though to be certain many of these are small prospects, and a handful of large mines on the Illinois side accounted for 75% of modern production. The district supplied over 90% of the US fluorite production, and large amounts of lead, zinc and barium were also recovered (Goldstein 1997). Unfortunately while the huge fluorite reserves in the district are probably far from depleted, rising production costs and cheap imported Chinese fluorite made mining economically unfeasible in the late 1990\u2019s, and the last mine, the Annabel Lee, closed in 1996, marking the end of over 200 years of fairly continuous mining in the Illinois-Kentucky Fluorspar District.<\/p>\n
Geologically, the Illinois-Kentucky fluorspar district seems deceptively simple, but in reality is part of a complex and still-poorly understood region which has been affected by processes ranging from faulting to sedimentation to unusual igneous intrusions. The surface and near-surface (upper few kilometer) geology is dominated by sedimentary rocks ranging from middle Devonian to early Pennsylvanian in age (Goldstein 1997). The fluorite-barite-galena-sphalerite orebodies occur as two generalized types, bedding-replacement deposits which are mainly horizontal and controlled by stratigraphy, and steeply-dipping veins which follow structures and can extend to great depths. Really, these two ore deposit styles are probably related, as the \u2018bedding replacement\u2019 deposits require a structural conduit for mineralizing fluids to reach a favorable limestone bed where replacement can occur. Both orebody types occur in a large anticlinal structure known as Hick\u2019s Dome, whose uplift is probably related to regional compression as well as emplacement of a potential (never interested by drilling) deep alkalic intrusion, which may have been the source for fluorine for the deposits. The Illinois-Kentucky fluorspar district sits in the most heavily faulted area of the Midwestern USA, and these faults provided the \u2018structural plumbing\u2019 necessary for creation of the numerous ore deposits. The \u2018smoking gun\u2019 showing genetic connection between alkalic intrusive rocks and the fluorite deposits would probably involve isotope and trace element geochemical work, testable by modern methods, but little serious research on the fluorite deposits has occurred since mining ceased in 1996. Current literature suggests that locally-derived brines (salty fluids) from probably evaporitic beds within the limestone package mixed with magmatically-derived fluids, which may have triggered mineralization and precipitation of fluorite (Grogan & Bradbury 1967). Whatever the case, the combination of large, extensively-mineralized areas and a propensity for brecciation and attendant open pocket formation in the district proved to be a bonanza for mineral collectors.<\/p>\n
Without a doubt, the premier mineral from the Illinois-Kentucky fluorspar district is, as the name suggests, fluorite. Fluorite from the district probably shows more variation in color than at any other locality, ranging from purple to blue to yellow to gray to pinkish and every shade in-between. The only \u2018dominant color\u2019 missing is the rich greens of the North Pennines Ore Field fluorites from the UK, though green crystals were found rarely in several of the older Illinois mines. Perhaps most famous and coveted are the large, gemmy groups of cubic crystals showing crisp color zonation, typically yellow with violet edges or vice-versa, from mines such as the Annabel-Lee, Minerva #1, and Denton. Most of these came out from ~1980-1995, and pockets were often so abundant during this period that high-quality fluorite sold either by the pound or by \u2018the table\u2019 at shows or at a miner\u2019s residence. Competition for top specimens was fierce, however, and prominent dealers in the region such as Ross Lillie, Dan Weinrich and Mark & Joe Kielbaso have many stories about racing down to Cave-in-Rock or Rosiclare to see \u2018the next big find\u2019 moments ahead of their competition (Goldstein 1997). <\/p>\n
The early years (~1900-1950) of fluorite production included important specimen-producers such as the W.L. Davis-Deardorff mine, which produced delicate violet fluorite crystals on a distinctive drusy quartz matrix, and the Hill-Ledford, which produced some of the largest single fluorite crystals in the district, up to 45 cm across! Sadly, as they had little value at the time due to their perceived commonness, many were either damaged upon removal, or broken down into \u2018spar octahedrons\u2019 which are produced by exploiting fluorite\u2019s two perfect cleavage directions with a small hammer. During this period, many fine examples of galena and sphalerite were also found, with galena crystals from the Hill-Ledford mine sometimes reaching 15 cm on edge. The Minerva #1 mine, discovered somewhat accidentally when a night-shift driller salted their drill hole cuttings to hide their nighttime work absences, became the premier locality for the rare barium minerals witherite and benstonite from the late 1940\u2019s up to the 1980\u2019s (Goldstein 1997). Witherite occurs there as sharp white to yellow barrel-shaped crystals up to 15 cm, sometimes aesthetically isolated on fluorite or barite matrix. <\/p>\n
Witherite: Minerva #1 Mine, Cave-in-Rock, Hardin County, Illinois, 7.5 cm (photo \u00a9 Joe Budd\/irocks.com)<\/p><\/div>\n
Barite is another fairly ubiquitous species from the Illinois-Kentucky fluorspar district, with the best crystals coming from the Minerva #1 and Denton mines, often associated with colorful fluorite and calcite. In the 80\u2019s and early 90\u2019s, the Denton and Annabel-Lee mines amazed the world with their brilliantly lustrous, golden-yellow calcite crystals, often as large twins on matrix. Celestine, a somewhat rare mineral for the district, was found as excellent blue-gray crystals to 5 cm on fluorite from the Annabel-Lee mine (Goldstein 1997). Galena, having previously consisted of sharp but somewhat dull crystals from the W.L. Davis-Deardorff and Hill-Ledford mines, was found as brilliant cubo-octahedrons on purple fluorite at the Denton mine. Many fluorite crystals show fascinating dissolution textures, where later fluids have corroded them into bizarre shapes and sometimes deposited new minerals, such as paralstonite and smithsonite. Strontianite in attractive yellow to white sprays was sometimes associated with these altered fluorite crystals as well, and occasionally, perfectly circular \u2018holes\u2019 would be seen in otherwise unaltered fluorite crystals where inclusions of spherical barite had dissolved, sometimes called \u2018drillholes\u2019 by the miners. While current economic conditions are not bright for the return of fluorite mining to the Illinois-Kentucky fluorspar district, the good news is that the sheer number of specimens produced means that every collector can own a piece of this world-class mineral locality for many years to come.<\/p>\n
7.) Bisbee, Cochise County, Arizona USA<\/strong><\/p>\nBisbee Masonic Lodge holding a 1887 meeting in a huge \u2018cave\u2019 in the Copper Queen Mine, Bisbee, Arizona (photo \u00a9 Library of Congress)<\/p><\/div>\n
Bisbee, situated in the rolling scrub oak hills of far southern Arizona just north of the Mexican border, is a world-class mineral locality in every sense of the word. From the late 1870\u2019s up until 1975, Bisbee produced 3.6 million tons of copper, 161,000 tons of zinc, 147,000 tons of lead, 100 million ounces of silver, and 2.7 million ounces of gold, making it one of the richest mining districts in the world for its size (Graeme 1981). Bisbee\u2019s lasting legacy, however, will probably have more to do with the thousands of fine and colorful mineral specimens it produced than metal statistics. Collections all over the world include crystals of azurite, malachite, native copper, calcite, and more from Bisbee mines. Additionally, while mining for copper at other metals no longer takes place at Bisbee and the community has embraced a more artistic side and tourism, research on the ore deposits is ongoing and many new species, both to the district and to science have been discovered since mining stopped.<\/p>\n
Cuprite (2.5 cm. crystal) on malachite from the Southwest Mine (specimen and photo \u00a9 Richard Graham)<\/p><\/div>\n
The mining history of Bisbee is fairly recent, beginning in the late 1870\u2019s when prospectors Jack Dunn and George Warren visited the area from nearby Tombstone, a recently-established silver camp, and noted abundant outcrops of colorful gossan, a good indicator of mineralization at depth (Graeme 2008). They worked the near-surface ores over the next several years, ad eventually the Copper Queen mine was developed in the early 1880\u2019s. The Copper Queen, a series of high-grade supergene orebodies in Naco limestone, featured not only high copper grades but spectacular \u2018caves\u2019 lined with stalactites of azurite, malachite, and other secondary copper minerals. Thanks to the foresight of these early miners, many of these specimens were preserved in prominent East Coast museum collections, but many more were destroyed and melted down for their copper content during mining. Mining accelerated in the 1880\u2019s and 90\u2019s as additional high-grade, near-surface copper orebodies were discovered, and Bisbee quickly grew into a typical frontier \u2018boom town\u2019, with businesses crowded into the narrow Brewery Gulch downtown. <\/p>\n
Azurite with Malachite: Czar Mine (14.5 cm across; specimen and photo \u00a9 Joe Budd & irocks.com)<\/p><\/div>\n
James Douglas started the Phelps & Dodge Mercantile company, which acquired claims adjacent to the Copper Queen which ended up propelling the company into one of the world\u2019s largest copper producers of the 20th century, the famous Phelps Dodge Corporation. The Copper Queen mine operated independently by the Copper Queen Mining Company, but after ~1920, pressures to consolidate meant that the mines were acquired by Phelps Dodge, which ruled mining in Bisbee for the next 50+ years (Graeme 2007). Mines such as the Czar, Holbrook, Copper Queen, Southwest, and Junction mined fabulously rich and extensive copper ores, with significant recovery of Au, Ag, Pb, & Zn as well. Miners were long aware of the value and beauty of good mineral specimens- many anecdotes exist about miners trading fine minerals for haircuts, drinks, and often cash from visiting mineral dealers and museum curators (Graeme 2008). The final chapter of mining at Bisbee involved the type of large tonnage, low-grade open pit mining now favored in Arizona, focused on the porphyry from which most of the high-grade veins and carbonate-replacement deposits originated. This mine, the Lavender Pit, is still quite visible today, dominating the south end of Bisbee. Relatively small-scale mining of some remaining high grade portions of orebodies in the Junction and Holbrook mines continued into the early 1970\u2019s as well, but these closed eventually due to rising costs and lower yield (Graeme 2008). <\/p>\n
Spinel-twinned group of Native Copper Crystals: Bisbee, Arizona (5.3 cm, specimen and photo \u00a9 Joe Budd & irocks.com)
<\/p><\/div>\n
The geology of Bisbee has been studied in detail since Frederick Ransome of the U.S. Geological Survey published his landmark monograph in 1904. Bisbee, like much of southern Arizona, in underlain by Precambrian schist and quartzite of the Pinal group, which in turn is overlain but 1600-2000 meters of mostly Paleozoic sedimentary rocks, dominantly limestone (Graeme 2008). Beginning in the Jurassic period ~180 million years ago, igneous activity and associated faulting introduced massive amounts of pyrite to the Bisbee area, which replaced selective limestone beds and also was associated with minor copper, silver and gold (Anthony et al. 1995). Later, during regional extension associated with basin-and-range tectonics across southern Arizona in the Cretaceous to Eocene periods, many large copper-bearing porphyry intrusions were emplaced, including Ray, Morenci and Bagdad. At Bisbee, however, a similar copper porphyry, the Sacramento stock was emplaced much earlier, around 104 million years ago, and high-grade vein deposits were probably concurrent with this intrusion (Bain 1952, Anthony et al. 1995). Lead-zinc deposits of the carbonate-replacement type were formed during this event, and finally, somewhat later, a third major pulse of mineralization overprinted some earlier Cu-Pb-Zn deposits, enriching them in unusual metals such as tin, bismuth, tungsten, tellurium, and antimony (Graeme 2008). Uplift and erosion during the more recent Eocene period led to the devlopment of extensive supergene enrichment zones in many deposits, in which most of the colorful and well-crystallized minerals reside. It is this complex and multi-stage geologic history that gave Bisbee its unique mineralogy.<\/p>\n
The mineralogy of Bisbee is rich and varied, with over 322 mineral species reported (Graeme 2008). The ores are often highly complex, with assemblages of rare tin, tungsten, and tellurium minerals that are just beginning to be understood. Of course, the stars of Bisbee are azurite and malachite, both occurring in quantities large enough to be considered major ores in the early years. Crystals of azurite from Bisbee occur in a variety of forms, from classic \u2018rosettes\u2019 of flattened blocky crystals, to elegant prismatic blades to 10+ cm on matrix. Tsumeb and the new Milpillas mine not far from Bisbee may be close competitors for the title of \u2018world\u2019s best azurite\u2019, but Bisbee can hold its own, specimen-for-specimen, with most anything from these locales. Malachite often replaces azurite at Bisbee, and sharp psuedomorphs in clusters to 20+ cm are a specialty. Cuprite is another species for which Bisbee is world-renowned, with the best specimen consisting of 2.5 cm, lustrous, gem-red crystals on malachite; truly a spectacular piece. \u2018Chalcotrichite\u2019, or fibrous nests of cuprite needles, is common, often associated with native copper. Native copper was locally abundant at numerous levels in the major mines, and fine crystals, often showing spinel-law twinning, occur in hand to basketball-sized groups, giving the Michigan Copper Country a \u2018run for its money.\u2019 Calcite is a particularly varied and beautiful Bisbee mineral, often colored by inclusions of various copper minerals, resulting in bright red or green to blue groups. The \u2018caves\u2019 of the early supergene enrichment zones contained huge quantities of \u2018floss ferri\u2019 aragonite and delicate groups of calcite crystals showing stalactitic growth features. <\/p>\n
Spangolite with cuprite: Czar Mine, Bisbee, Arizona: crystals to 1.7 cm (photo & specimen \u00a9 Harvard University)<\/p><\/div>\n
Bisbee is the type locality for 7 species, including the rare and beautiful copper minerals Spangolite and Paramelaconite, both highly prized today. Shattuckite, another rare copper mineral, was also discovered at Bisbee. Turquoise, while not associated with historic mining at Bisbee, was found in considerable quantity and quality in more recent years adjacent to the Lavender open pit. Paratacamite, Covellite, Conichalcite, Claringbullite, Conellite, Chalcoalumite (TL), and brochantite are colorful and reasonably abundant at Bisbee, despite being globally rare copper minerals. Recent research on Bisbee has added numerous new species to the list, and the previously ignored \u2018massive sulfide ores\u2019 of deep mines like the Campbell and Holbrook are now recognized as having very unusual geochemical signatures, with strong enrichment in indium, gallium, tungsten, tin, and tellurium, suggesting the genesis of the deposits likely involved multiple geochemically unusual hydrothermal fluids. Phelps Dodge successor Freeport-McMoran has been considering re-opening and expansion of the Lavender pit in Bisbee in recent years, so when copper prices improve, we may once again see mining return to the great town of Bisbee (Jaworski pers. comm. 2014). <\/p>\n
8.) The Ojuela Mine, Mapimi, Durango Mexico<\/strong><\/p>\nFamous Roebling Suspension Bridge at Ojuela (photo \u00a9 mexconnect.com)<\/p><\/div>\n
Mention the Ojuela (pronounced O-whale-ah) mine to collectors and visions of vibrant green Adamite pinwheels, neon yellow Legrandite sprays, and rich orange Wulfenite groups are sure to be conjured, or perhaps the 310 meter length of the famous Roebling suspension bridge, the longest in Latin America, contrasting with rugged desert landscapes. The Ojuela mine, located in the state of Chihuahua close to its border with Durango in north-central Mexico, is home to over 137 mineral species, with 7 of them having their type locality there. Over 6 million kilograms of silver and 49,000 kilograms of gold were produced from Ojuela, in addition to substantial lead and zinc, totally in value to over 2 billion dollars in nearly 400 years of production (Panczner 1987). Its history is rich as well, from the discovery of the deposits by Spanish Jesuit priests in 1598 up until today, where mining, mainly for mineral specimens, is ongoing (Haghenbeck & Haghenbeck 2011).<\/p>\n
Famous \u2018Aztec Sun\u2019 Legrandite; ~20 cm, Ojuela Mine (photo \u00a9 Jeff Scovil & the Mineralogical Record)<\/p><\/div>\n
Mining for silver began in the early 17th century and continued at a small scale before accelerated in the mid-19th century with the importation of modern mechanized mining methods from Europe and the USA. To solve the conundrum of connecting mining operations with the town located across a deep, rocky gorge, a huge pedestrian suspension bridge measuring 310 meters across was constructed in 1898 by John Roebling & Sons (Haghenbeck & Haghenbeck 2011). John Roebling\u2019s son, Washington Roebling, was a leading mineral collector of his era, so the improvement of Ojuela, already then known for fine minerals, must have been of particular satisfaction to him. Mining at Ojuela continued to grow up until the Mexican revolution in 1910, when the country was swept into chaos and Penoles, the large mining conglomerate in charge of operations, was nationalized (Haghenbeck & Haghenbeck 2011). After the revolution, mining continued, eventually creating over 450 kilometers (!) of underground workings. Large-scale mining ceased in 1945, but since that time, small groups of miners organized under collectives or cooperatives have produced a mix of silver-polymetallic ore and mineral specimens. Mineralogists of the early 20th century such as W.F. Foshag and Dan Mayers helped popularize the unusual and colorful minerals of Ojuela, and miners found that they could make better wages collecting crystallized minerals than mining ore, a tradition that has continued up until today.<\/p>\n
Adamite \u2018pinwheels\u2019 on matrix to 4 cm from the Ojuela Mine (photo \u00a9 Jeff Scovil)<\/p><\/div>\n
The geology of the Ojuela Mine and the Mapimi region is dominated today by typical basin-and-range topography and structure, with similar mountain ranges, valleys and landscapes to Southern Arizona or New Mexico. Precambrian age granite and schist is overlain by a thick sedimentary sequence, dominated at Ojuela by Cretaceous limestones and dolomites (Panczner 1987). The Ojuela mine exploits not one but seven different pipe-like orebodies, called \u2018chimneys\u2019, and associated \u2018mantos\u2019, or carbonate-replacement orebodies controlled mainly by stratigraphy. These chimneys and manto deposits extend to depths of over 900 meters, with oxidation occurring at depths of up to 500 meters (Panczner 1987). Similar to Tsumeb, this great depth of oxidation and supergene enrichment couples with \u2018receptive\u2019 carbonate host rocks are largely responsible for Ojuela\u2019s great mineralogical diversity. 4 main mineralization styles occur at Ojuela: copper-enriched \u2018contact\u2019 ores, lead-zinc ores, silver-lead ores, and the \u2018barren\u2019 carbonate zone (Panczner 1987). Each of these zones contains different minerals assemblages. <\/p>\n
Mineralogically, the Ojuela mine is perhaps most famous for its arsenate (arsenic-containing) secondary minerals, such as adamite, legrandite, and kottigite. Adamite, perhaps the most famous mineral from Ojuela, occurs as spectacular \u2018pinwheels\u2019 on vibrant green crystals to several cm each, as well as sharp individual crystals, typically on an aesthetically-contrasting gossan matrix. Cuprian adamite is relatively abundant at Ojuela and has a distinct blue-green shade different than copper-free adamite. The most desirable, however, is the manganoan adamite, colored purple and occurring as vivid bundles of crystals to 5+ cm on matrix. These purple adamites caused quite a stir in the mineral world when a major pocket was discovered in 1981, and Texas oil man Perkins Sams spent many thousands of dollars of several top examples now in the Houston Museum of Nature & Science. While adamite is still being found at Ojuela, most modern production consists of small crystals in vugs in matrix, and it appears the often very large (and very inexpensive by modern standards), plates of pinwheels or bladed aggregates of crystals are a thing of the past. <\/p>\n
Wulfenite on Mimetite: Ojuela Mine (7 cm, specimen and photo \u00a9 Joe Budd & irocks.com)<\/p><\/div>\n
A close second to adamite from Ojuela is legrandite, another rare zinc arsenate species which reaches its zenith at Ojuela. Probably the most famous specimen, consisting of an aesthetic \u2018V\u2019 pair of sharp yellow crystals to 20 cm(!) is known as the \u2018Aztec sun\u2019 and for many years was the centerpiece of the Dr. Miguel Romero collection (it is now in the MIM museum in Beirut). Its sale and the extraordinary price (rumored to be around $2 million USD) associated with it also became a talking point in the mineral community, and in a curious case of \u2018trickle down economics\u2019, all other legrandites, even thumbnails, seemed to see a concordant increase in their price tags. Nonetheless, enough legrandite was produced that the average collector can still acquire a modest example of this beautiful and classic species from the Ojuela Mine.<\/p>\n
Other rare and beautiful arsenate species from Ojuela include brilliant green Austinite crystals, blue Kottigite sprays, and blue-gray Symplesite blades. Equally famous (and much more abundant today) are specimens of green, botryoidal mimetite hosting lustrous orange wulfenite crystals, up to several cm in size. Wulfenite from Ojuela is somewhat unusual in its variety of crystal forms: almost equant, pseudo-cubic crystals are not uncommon, as are elongated, dipyramidal crystals. In recent years, many excellent, very aesthetic examples of this combination have been found. Hemimorphite is another attractive zinc mineral which is abundant at Ojuela- groups of parallel white prisms forming an almost botryoidal \u2018carpet\u2019 on gossan matrix have been found up to 40+ cm. Several minerals also noted from Tsumeb occur as attractive examples from Ojuela, such as bayldonite, tsumcorite, and duftite. Additionally, Ojuela is the type locale for a number of species, including the rare arsenates lotharmeyerite, mapimite, ojuelite, and miguelromeroite. Continued mining by cooperatives and independent specimen diggers mean that good minerals and perhaps new species will be found at Ojuela for many years to come.<\/p>\n
9.) San Diego County, California Gem Pegmatites<\/strong><\/p>\nFamous 25 cm-wide \u2018cadelabra\u2019 blue-capped Elbaite Tourmaline from the 1972 Tourmaline Queen Mine find (photo \u00a9 Harold & Erika Van Pelt)<\/p><\/div>\n
Gem pegmatite districts, typically of the Lithium-Tantalum-Cesium (LCT) pegmatite family, are not especially rare on earth, with good examples occurring on most continents, including the mountains of Pakistan\/Afghanistan, Minas Gerais State in Brazil, and Oxford County Maine, USA. What makes the pegmatites of Southern California special however, is their concentration, both of individual pegmatites and of collectible (and often beautiful) mineral species. While gemmy, polychromatic crystals of tourmaline, spodumene or beryl first come to mind when San Diego County in invoked, the district is also an important source of fine crystallized examples of rarer species such as stibiotantalite, rynersonite, hydroxlherderite, and hambergite. Mining for gemstones and mineral specimens has enjoyed an almost 125 year history, continuing today, and interest and appreciation for the minerals of the region, particularly tourmaline, are probably at an all-time high today.<\/p>\n
George Kunz examining crystals of spodumene var. Kunzite around 1905.<\/p><\/div>\n
A large kunzite crystal in the Harvard collection from the same find (both photos \u00a9 Bill Larson\/palaminerals.com)<\/p><\/div>\n
The rolling, Mediterranean-like hills around Mesa Grande and Pala were quite pastoral in the late 19th century, with farming and ranching occurring around scattered small villages. In 1898, Mesa Grande local Gail Lewis discovered small crystals of bicolor tourmaline loose on the surface of what would become known as the Himalaya pegmatite, and filed a claim on it. Given the strong market for US gemstones at the time, the chief promoter of this market, George Kunz of the Tiffany company of New York, soon got word of the new California tourmaline discovery, and sent secret company agents to investigate the potential for a new gem district (Fischer 2008). Kunz\u2019s men soon began mining tourmaline and other pegmatite minerals at the Himalaya and nearby pegmatites on their own, with most good colored tourmaline going to China for carving into ornamental snuff bottles and other items which were then very much in demand there (Fischer 2008). In 1902, the pegmatites around Pala were discovered, and soon after, a number of crystals of bright pink spodumene were found, to be named \u2018kunzite\u2019 in honor of George Kunz. After the Chinese revolution in 1912, demand for carving-grade tourmaline plummeted, as did gem demand in general in the US around the world war periods (Fischer 2008). It was not until the 1950\u2019s, as mineral collecting became increasingly popular in the US along with demand for colored gems that pegmatite mining resumed in San Diego and Riverside counties. Several spectacular discoveries in the 1970\u2019s and 80\u2019s, most notably the 72 find of huge blue-capped pink tourmaline crystals at the Tourmaline Queen Mine. Mines such as the Stewart, Tourmaline King & Queen, Himalaya, and Little Three enjoyed fairly frequent pocket discoveries throughout the middle 20th century, and some are still operating today, though generally on a \u2018hobbyist\u2019 or \u2018weekender\u2019 level by collectors with other primary forms of employment. Indeed, the challenges of pegmatite mining are perhaps best exemplified by the months leading up to the great 1972 \u2018blue cap pocket\u2019 at the Tourmaline Queen Mine, in which miner John McLean and others tunneled over 6 meters through hard, unmineralized, barren pegmatite only to change course slightly into a world-class crystal pocket (Larson 2008). Still though, the search for gems has inspired many a miner and collector, and this search continues today at mines such as the Oceanside and Cryo-Genie.<\/p>\n
Stibiotantalite crystals on Rubellite Tourmaline (2.6 cm across), Himalaya Mine (specimen and photo \u00a9 irocks.com)<\/p><\/div>\n
Geologically, the gem pegmatites of San Diego County share many similarities with other great gem pegmatite provinces of the world. They are of the lithium-tantalum-cesium (LCT) geochemical family, which are highly evolved pegmatites characterized by stong enrichment in large ion lithophile (LILE) elements such as lithium, cesium, rubidium. They also contain significant boron, fluorine and beryllium, important elements for the formation of tourmaline, topaz, and beryl. Additionally, many pegmatites can be subdivided into rare element (containing minerals such as stibiotantalite and samarskite-(Y)), and phosphate (containing large \u2018nodules\u2019 of various phosphate minerals) affinities. In San Diego County, these pegmatites have intruded Cretaceous-age granite plutons of the Peninsular range batholith (Fischer 2008). Pegmatites have been dated at ages of ~93-98 million years, while the main host granite is ~101 million years old (Fischer 2008). This age relationship is typical for highly evolved gem pocket-bearing LCT pegmatites, which form as residual granite melt becomes increasingly enriched in incompatible elements, water, and other volatiles and eventually intrude surrounding, already cooled rock to form much coarser-grained, chemically-complex dikes. Many of the gem-producing pegmatite\u2019s of San Diego County extend along their strike for 100\u2019s of meters, but are only 1-2 meters thick, with spectacular mineral zonation. Unidirectional solidification textures (formed as undercooled magma crystallizes against cold wallrocks) show large euhedral crystals which point inward perpendicularly from pegmatite walls, and at their terminations, a core zone enriched in massive lepidolite, tourmaline and other rarer species may sometimes open up into the much-coveted miarolitic gem crystal pocket. While many pegmatites are strongly deformed by subsequent uplift and faulting, the arid climate combined with fairly near-surface (<5 km) emplacement of the pegmatites means that exposure is excellent, and almost all pegmatites known today were discovered from surface outcrops. \n\nMineralogically, the San Diego County pegmatite district is fairly diverse, with over 120 minerals known from the pegmatites. The most famous mineral from San Diego County is probably tourmaline, or more specifically the lithium-bearing tourmaline species elbaite. Elbaite occurs in virtually all shades, from hot pink to deep blue to emerald green to nearly jet-black. Probably the most famous tourmaline crystals known today (we will avoid thinking about the many thousands of fine crystals which were destroyed by carving demand by the Chinese in the late 19th and early 20th centuries) are the large (up to \u2018beer can\u2019 size!) blue-capped rubellite crystals found in 1971 & 1972 at the Tourmaline Queen Mine. The nearby Tourmaline King pegmatite also produced outstanding, sometimes very large \u2018watermelon\u2019 and green-capped pink crystals during this era, sometimes in clusters up to 30 cm. The famous 28 cm-high \u2018steamboat\u2019 specimen on display at the Smithsonian is one such example. The Stewart mine produced thousands of elongated rubellite crystals with distinctive \u2018hot pink\u2019 color, and similar crystals were found at the Pala Chief mine (Fischer 2008). In the 1980\u2019s and 90\u2019s, many fine elbaite crystals showing horizontal color bands of blue, green and pink were found at the Himalaya mine. Recently, large sprays of similarly color-zoned crystals with curious \u2018tapered\u2019 habit have been found at the Cryo-Genie mine. Fine tourmaline continues to be found today in San Diego County.\n\nNext in fame to tourmaline is probably the beautiful pink variety of spodumene, kunzite, first discovered in the Pala Chief mine and nearby Katerina and Vanderberg pegmatites in the early 20th century. Kunzite occurs as flattened tabular, gem-clear pink crystals up to 28 x 15 cm! Indeed, the largest known Southern California kunzite was actually just discovered in 2010 at the Oceanview pegmatite. Beryl also occurs in numerous varieties from heliodor (yellow-green) to goshenite (clear), but probably the most famous crystals are the sharp, gemmy flattened hexagonal pink morganite crystals from pegmatites such as the White Queen, Oceanside and Elizabeth R. Attractive clear to light blue beryl crystals also occur at pegmatite\u2019s including the Beebe Hole and Pack Rat (Fischer 2002). Topaz is somewhat less common in San Diego County, but does occasionally form excellent, gemmy light blue to clear crystals to 10 cm, most notably at the Little Three mine, which has also produced striking combinations of gemmy spessartine garnet with schorl tourmaline on albite (Fischer 2002). \n\n[caption id=\"attachment_835\" align=\"aligncenter\" width=\"498\"] Blue Topaz: Little Three Pegmatite (photo \u00a9 Robert Weldon\/GIA)[\/caption]<\/p>\n
Notable rarer species from San Diego County pegmatites include dark red, lustrous crystals of Stibiotantalite with rynersonite (type locality), both rare tantalum oxides. Fine yellow to brown crystals of danburite, a boron species which is occasionally found in evolved LCT pegmatites, were sometimes found at several pegmatites. Hambergite, a rare boron beryllium siicate, is found in good crystals at several pegmatites as well, only recently eclipsed by spectacular discoveries in Madagascar and Pakistan. While not quite as aesthetic, the rare species boromuscovite was first discovered at the Little Three mine, where it is reasonably abundant. Nice pink to clear crystals of fluorapatite were often associated with quartz, though the most desirable apatites are attached to vibrantly-colored tourmaline crystals, making handsome specimens. Numerous rare phosphate minerals, such as jahnsite and hureaulite also are found in a number of San Diego County pegmatites. Continued mining in San Diego County means that fine mineral specimens will likely be available for many years to come.<\/p>\n
10.) Jachymov District, Bohemia, Czech Republic<\/strong><\/p>\nJachymov Village in winter (photo \u00a9 prague-guide.co.uk)<\/p><\/div>\n
This last, but certainly not least locality was a difficult choice for many reasons, the obvious being that there are dozens of other localities around the world that could be considered \u2018top ten\u2019, and I\u2019m many a reader is groaning at this very moment about my failure to include their favorite locality. Another is that there are numerous other \u2018world-class\u2019 districts in Europe which are geologically quite similar to Jachymov, such as Freiberg, Germany and Kongsberg, Norway. Nonetheless, I think Jachymov is a worthy addition to the somewhat arbitrary \u2018top ten\u2019 list for several reasons. While often forgotten by modern collectors due to scarcity of good specimens on the market and the fact that most mining occurred so long ago, Jachymov is in fact a mineralogical powerhouse, with 429 minerals reported from the district, and 46(!) of these being type localities. Many of these type locality species are not obscure, ugly rarities but in fact globally-important minerals, including uraninite, bornite, and yes, fluorite! This begins to hint at the historical importance of the district in establishing the science of descriptive mineralogy, and the centuries-long mining history there. Additionally, Jachymov is probably the world most important example of the economically-important \u20185 element vein\u2019 type of ore deposit, which will be discussed more in detail later.<\/p>\n
Proustite crystal group from Jachymov (4.5 cm across; photo & specimen \u00a9 Weinrich Minerals)<\/p><\/div>\n
The Jachymov District (also known as the Joachimsthal District) is situated in the Erzgebirge (literally \u2018ore mountains\u2019 in German) mountains, a range of mainly low (<2000 m), rolling, heavily forested mountains near the German border with the northwestern Czech Republic. The history of the district stretches back to the beginning of the 16th century, when the Kingdom of Bohemia ruled the region (Majer & Podlesi 1994). In 1516, rich silver veins were discovered in outcrop at Jachymov, and such a mining rush was created that production at the already well-established mines in nearby Saxony was significantly depressed, and banks and well-to-do merchants all over central Europe scrambled to invest in mining there (Majer & Podlesi 1994). By 1520, over 4000 miners and their families inhabited the \u2018free mining town\u2019 of Jachymov, and this rose to over 13,000 by 1525 (Majer & Podlesi 1994). The main purpose of mining at Jachymov in this era was production of silver to provide currency for the Kingdom of Bohemia, and it did so quite well, with over 2.2 million coins already produced by 1528, from 25 open pit and underground mines (Majer & Podlesi 1994). Indeed, even modern currency owes a nod to Jachymov, as the coins minted there were originally called \u2018Joachimsthalers\u2019, or \u2018thalers\u2019, which was corrupted over time to the word \u2018dollars\u2019 (Tyler 1930). Unfortunately, the rich, near-surface silver ores were fairly exhausted by 1550, and Jachymov lay somewhat dormant for a period, though some mining for silver continued, as well as for elements such as nickel and cobalt (then used as a pigment in paints). However, a new boom would come much later, thanks to the presence of a mysterious dense, black colloform mineral the miners called \u2018pech blende\u2019 or \u2018black ore\u2019, which would turn out to be uraninite (pitchblende). Scientists as early as the great 16th century metallurgist and early mineralogist (though a physician by training) Georgius Agricola noted the \u2018bad health effects of inhalation of pech blende dust\u2019, though he had no idea this was caused by exposure to radiation. \n \n[caption id=\"attachment_838\" align=\"aligncenter\" width=\"580\"] Illustration from Georgius Agricola\u2019s seminal 1556 book \u2018De Re Metallica\u2019 illustrating mining at Jachymov (photo \u00a9 fotosearch.com)[\/caption]<\/p>\n
Fast-forward 300 years to the mid-19th century, when it was found that uranium salts, when added to ceramics, could produce beautiful shades of neon green, yellow and red, and the ceramic industry of Bohemia for many years featured brightly-colored enamelware made with such additives (Frame 2015). Later, when Marie Curie isolated the element radium, the rich uranium ores of Jachymov became a main source for this miraculous new element, whose curative powers (when applied to chemotherapy) were recognized early, but whose negative powers (to create the very cancer and other ill health effects it sought to cure) were regrettably not understood until much later. During Victorian times, people all over Europe rejoiced in the supposed curative powers of radium, and items such as radium toothpaste, mouthwash, and \u20185 cent x-rays\u2019 were touted for their health effects (Frame 2015). In 1912, the \u2018Marie Curie-Sklodowska Radium Palace\u2019 opened in Jachymov, where visitors could bathe in geothermal springs, which supposedly contained radium, and indulge in various radium health treatments. Unfortunately by the time Marie Curie herself realized the deadly reality of radium, she was already in the advanced stages of terminal thyroid cancer, but her scientific discoveries would and had already changed the world, and would pave the way for the next era of mining at Jachymov. After WWII, when Bohemia and Jachymov descended behind the \u2018iron curtain\u2019 of the Soviet Union, Jachymov became a strategic asset, and the larger East German region was the number one supplier of uranium for both energy and nuclear arms to the USSR (Frame 2015). From 1948 to 1962, thousands of laborers, many of them political and other prisoners, labored in the Jachymov mines to extract uranium ore. All of this was highly clandestine, of course, and much is still unknown about Jachymov during this period. By the fall of the iron curtain and the breakup of the Soviet Union in the early 1990\u2019s, mining was mostly gone at Jachymov. Today, the town is somewhat is disrepair, having never economically recovered from the cessation of mining and state planning of every detail of life there during Soviet times, but a modest tourist industry caters to those interested in the fascinating history of the area, as well as several nearby health spa resorts.<\/p>\n