Field Trip: Midwestern Geode Localities


By: Jeremy Zolan

Difficulty Level: Easy to Medium

Supplies Needed:
Safety Goggles
Water
Insect Repellant
Shovel
Crack Hammer and Chisel
Paper for Wrapping Specimens
Bucket
Prybar (Optional)
Pick Axe (Optional)
Wheeler-Rex 590 Soil Pipe Cutter (Optional)

Search for Minerals from Iowa

Description:

View a map of the locations of these geodes by visiting MinDat.org’s copy of this map
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Geodes in the Warsaw formation of Iowa, Missouri, and Illinois. Each ‘x’ is a geode location. Originally from Arthur E. Smith (1997): Geodes from the Warsaw Formation of Missouri, Iowa, and Illinois, Rocks & Minerals, 72:6, 420-423. Updated and colorized by William W. Besse.

Many sites in the tri-state area of southeast Iowa, northeast Missouri and western Illinois produce geodes of world class quality. In fact, nowhere else in the world is richer in geodes than this strange area of the Midwest, where the Mississippian geode bearing Warsaw limestone formation is exposed near the surface. The geodes can reach 20cm across or larger and are mostly lined with quartz crystals though a variety of minerals like calcite, dolomite, sphalerite, and even millerite have been found in geodes. Geodes can be found wherever the Warsaw formation can be found outcropping. They can also be dug from riverbanks. Many fee dig sites for geodes are found in the areas of Iowa, Missouri, and Illinois rich in geodes.

wheelerrex-590-lg

A pipe cutter, specifically the model above (Wheeler-Rex 590 Soil Pipe Cutter) is great for opening geodes. Simply score the geode around the perimeter lightly with a hammer and chisel, clamp the cutter around the perimeter of the geode, and then carefully apply pressure until the geode splits. It is most desirable to split geodes into two equal sized hemispheres.

quartzgeodeiowa
Large quartz geode from Keokuk area- 20 cm diameter. Collected by David Wixom. K. Nash specimen and photo.

dolomiteiowageode
Typical geode and associated minerals (calcite and dolomite) from Keokuk, Iowa area. 4cm x 4cm. Rolf Lutcke specimen and photo. Ex. Paul Griswold

Localities:

Sheffler Rock Shop and Geode Mine:
RR1 Box 171
Alexandria, MO 63430
At junction of Highway 61 and 27, 6mi S of Alexandria

Tim Sheffler
(660) 754 – 1134
tsheffler@mchsi.com
$25 per day for 50 lbs of material. 75 cents for each additional pound

blackiowageodes
Calcite and quartz geode from the Sheffler Geode Mine. A good specimen for the locality. 10 cm wide. Roger Sedgwick specimen and photo. Collected by owner.

Geodes are very abundant at this locality, hence the high limit for material. They are typically filled with quartz crystals but some other interesting mineralization can be observed. Dolomite, calcite, and pyrite are common accessories. It is best to use a prybar to free the geodes from the limestone matrix and open them at home or wherever they can be carefully cleaned, opened, and sorted.

Des Moines River, Iowa and Missouri

Geodes can be found abundantly in the outcrops on the shores of the Des Moines river. Bring a shovel to loosen geodes from the muddy banks and wash them in the river so the surface features can be seen. Some rocks at these riverbank localities may be deceiving and look like geodes but are just cobbles that have been well-rounded by erosion. These geodes can be filled with a wide variety of minerals and be of extremely varying but most will only contain quartz and typically at most one other species such as calcite or dolomite.

Jacobs’ Geode Shop and Mine:
823 East County Rd 1220
Hamilton, IL 62341
(217) 847-3509

iowacollecting
Caption: Collector with large pile of geodes in Jacobs’ Geode Mine workings. E. Harrington photo.

Call before visiting. It is best to dig while the owners are around so they can show you the best technique to use at this site. It’s a good idea to call in advance to make sure they will be at the mine. The all day fee is reported to be $20. Apparently the owners only allow visitors to crack certain geodes on site so most of the prep work should be done at home. Reported to produce very nice material

calciteiowageode
7cm geode with 3.5cm calcite crystal. E. Harrington specimen and photo.

Modified by CombineZP
Marcasite crystal in geode. FOV 4.5mm. Collected and photographed by David Hanson.

Dennis Stevenson Geodes:
625 S. 18th St., Hamilton, Illinois
Call ahead to plan a trip: 309-337-3089 or 217-847-2952
$20 for one bucket, $15 for each additional one.

Mostly quartz based geodes, but some have nice calcite crystals as well. A staple Midwestern geode locality.

Find out what minerals Iowa is and has produced, check out what is new on eBay

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Collecting Copper in Michigan’s Copper Country

Field Trip: Copper Country Collecting in Michigan’s Keweenaw Peninsula

By Jeremy Zolan

Difficulty Level: Easy to Moderate

Supplies Needed:
Safety Goggles
Water
Sunscreen
Insect Repellant
Crack Hammer
Chisel
Shovel
Wrapping Paper for Specimens
Bucket
Sledgehammer (optional)
Prybar (optional)
Metal Detector (optional)

Description:

The Keweenaw Peninsula of Michigan has been nationally famous for over 100 years for its history of highly productive copper mining. The local basalt is criss-crossed with many thick veins of native copper that made up the main ore of many of the mines. Solid natural masses of copper weighing hundreds of pounds were found with relative frequency at the mines. Though these pieces certainly were the most valuable ore, the best specimens from the area are clusters of well formed copper crystals. Other metallic minerals can be found with the native copper such as silver, domeykite, mohawkite, and chalcocite. Many other interesting minerals like datolite, analcime, prehnite, agate, and thomsonite are also abundant in the Keweenaw Peninsula. While all the mines of the region are closed to copper production, many are maintained as museums and fee dig sites. There are also many abandoned mines in the area that can provide good digging in the dumps but be sure to acquire permission from landowners before visiting any location on private land.

Localities:

Central Mine:
US 41
Central, MI 49950

central_mine_Michigan
Photo by Dave Maietta

Map:

The large tailings piles of the Central Mine are visible from US 41 in Central, Michigan. Many collectors have had good luck recently working this location. Occasionally, contractors remove large quantities of tailings for construction purposes and this exposes fresh material. In addition to the standard copper specimens, copper included calcite and prehnite can be found here. Silver has also been found with copper here but it is rare. A metal detector is very helpful for sorting trough dump piles like those found at the Central Mine.

central_mine_calcite
Caption: Calcite with copper inclusions. Central Mine, Central, MI 4.9 cm x 4.6 cm x 4 cm Ex. Rukin Jelks Rob Lavinsky Photo

Caption: Unusually large copper crystal. Central Mine, Central, MI. George Vaux collection at Bryn Mawr College. Scale bar is 1” long with rule at 1cm. Rock Currier Photo.central_mine_copper

Caledonia Mine:
Website: http://www.caledoniamine.com/
906-370-1131
202 Ontonagon St,
Ontonagon
Michigan 49953

The Caledonia Mine is a fee dig site that requires an advance reservation. When digging at this site, collectors are given a large pile of stockpiled copper ore and tools to go through it. Weekly collecting events on Thursdays and Saturdays are also held from the first Thursday in June to the last Saturday in August on the ore pile. Advance reservations are needed for these too. The workings of the Caledonia Mine are impressively preserved and tours are offered too. The mine tours aren’t necessarily just geared for casual guests. Many kinds of tours are offered, some with a very in depth historical or scientific focus. It is best to check the museum calendar to see if any events are happening during the time of your visit.

caledona_copper
Caption: Representative specimen of native copper from the Caledonia Mine’s recent workings. 5.6cm wide. Rob Lavinsky Photo

A.E. Seaman Mineral Museum
Website: http://www.museum.mtu.edu/
Michigan Technological University
1404 E. Sharon Avenue
Houghton, Michigan 49931-1295
E-mail: tjb@mtu.edu
Telephone: (906) 487-2572

Michigan Tech’s A.E. Seaman Mineral museum is among the finest mineralogical museums in the world. Its laboratories are also critical in performing much of the cutting edge mineral research currently being performed. During the period of most intense copper mining in Michigan, many specimens of local minerals were donated to the museum. Their collection of Michigan minerals is the finest in the world and there is a strong local emphasis on their displays.

Check out our custom search and view all the minerals from Michigan for sale on eBay. Not only will you see lots of neat stuff for sale, you’ll also get an idea of what localities are producing in the region.

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Cascade Canyon Ruby Crystals – A Los Angeles Hidden Gem

Ruby crystals found near los angeles glow bright red under long wave UV light.

Cascade Canyon, located exactly 1.7 miles southwest of Mt. Baldy, is the home to many interesting, if small, minerals and veins of interesting polishable minerals. Collecting around the top and bottom of the canyon, we have found various qualities and sizes of corundum var. ruby along with small veins of beautiful, if hard to come by, pieces of lapis. In addition, we have found minerals that the area is not well known for, including small dravite crystals, epidote, diopside and uv reactive calcite.

1.7 miles from Mt. Baldy, on the south side of cascade canyon, ruby crystals are found.

The lapis deposit is near the top of the mountain, with no access that would be considered even reasonably obtainable by anyone who is not well versed in mountain climbing. In addition, the area of the deposit was covered in an avalanche years ago. Anyone attempting to reach this deposit would be doing so at risk of life itself. In the upper streams of cascade canyon, before it turns into what would be impassible for most, bits and pieces of lapis can be found. Most people we have interviewed who have collected there in the past are happy with one visit to the location.

On Barrett-Stoddard Road, though closed to vehicle traffic, you can find interesting mineralization along the roadside, which is now a popular hiking/biking trail. Calcite veins with Diopside crystals have been located, however, the diopside is not crystallized well, with a melted appearance. The corundum locations along the roadside give the viewer a understanding that the deposit of “ruby” stretches along the entire mountainside.

Along the bottom of the canyon, on the south side of cascade canyon, along the area where the mountain follows the river on the lip of the eastern mountainside. While boulders of ruby bearing matrix can be found EVERYWHERE along the mountainside, the most popular collecting location is a small canyon that dumped out the contents of several rockslides into the valley below, creating a field rich with broken chunks of rocks with small ruby crystals inside.

Ruby crystals found near los angeles glow bright red under long wave UV light.

We were delighted to read Natalie Weisiger’s article about her trip to Cascade Canyon with the Gem and Mineral Council of the Los Angeles Natural History Museum. You can read about it, right here at http://omigems.com/blog/2013/07/california-corundum-from-the-ground-to-my-finger/ It is very interesting to read about the California ruby coming from the ground and into a piece of jewelry. You can certainly believe that is one unique piece of jewelry!


Natalie Weisiger in front of the landslide pile of ruby bearing rocks on the south side of Cascade Canyon

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Fossil shells replaced by calcite found in the roads of Central Texas

The Central Texas counties surrounding Limestone County are full of beautiful ancient marine shells replaced by calcite, both massive and crystallized. Luckily for the collectors of minerals and fossils, hundreds of miles of low traffic roads in Central Texas contain a wide variety of ancient sea life replaced by calcium carbonate. They are up on the surface of gravel and dirt roads, as snowy white gravel, stretching down the country lanes.
Calcite replaced marine shell
red, yellow and blue flowers along the countryside of central texas
This area of collecting is centrally located between Interstate 35 and 45. Those highways run through Texas, connecting San Antonio, Austin, Houston and Dallas. In between this area, vast deposits of limestone of a very high quality are found and mined for agricultural and industrial use. It is often found as crushed aggregate used to cover the stone roads of back country Texas. Spiraling out of the central texas area like a web connecting new developments with well maintained farm routes, the white roads of Texas are often found to contain calcite crystals and calcite replaced marine shell fossils. Clams, Brachiopods, Turritella, Ammonites and other interesting shells are found, often with cores and voids filled with crystals of calcite.
Fossil on matrix from central Texas replaced by calcite.
Getting to a collecting location is simple! Simply pull up Google Maps and take a look at a satellite view of Central Texas. As you get closer, look out for maintained county roads, which you will see, are bright white. This white color is caused by this limestone gravel. Make a note of these roads to inspect and take a trip to Marlin, Mart, Rosebud, Franklin, Calvert, Madisonville, and Crockett. Since there is ample loose gravel, do not DIG into the road or bother to take tools with you. Loose Gravel. Mostly made up of calcite replaced shells. What an amazing collecting experience. Simply opening your car door will result in you finding a loose fossil. With smartphones, androids and iphones, simply using google maps while navigating will be all you need for a spur of the moment collecting trip. This area is a little over 3 hours from San Antonio, a quick 2 hours from Austin, Houston and Dallas. It is a PERFECT field trip in all weather besides tornadoes and snow!
google satellite view of a typical white limestone gravel backroad in central Texas
a photo of the loose gravel limestone roads and the fossil containing gravel that is scattered across Texas

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