Overview: The Walworth Quarry, in Walworth, NY is a world famous locality for exceptionally clear, perfect fluorites. Once a year, the quarry owner, Dolomite Products, has an open house where they give collectors the unique privilege to dig in their quarry for world class mineral specimens.
This quarry dig is my personal favorite out of the two offered. Although the dolostone rock is extremely hard to break, fluorite and other highly collectable minerals are very abundant in this quarry. I would say it would be difficult to not find any fluorite. Sometimes it is so incredibly clear, that it can be hard to spot. Your eyes have to get used to searching for it, but once they do you will spot them all over the place.There are definitely enough to go around. This is an amazing trip I highly recommend to anyone in the Northeast who wants to find crystals.
Amazing fluorites found by the writer’s collecting partner Alexander Kim at previous Walworth open houses (Check him out on Instagram: @dirty_minerals).
Many other beautiful minerals are found at this quarry, the most notable being gorgeous golden sphalerites. Sometimes there will be droplets of tar like petroleum coating specimens. The petroleum can be removed with a organic solvent, but I think sometimes it really is aesthetically complimentary.
Two specimens found by the author: 1) A floater golden sphalerite crystal that was rolling around freely in a pocket with a few others that were attached to the walls. 2) A peculiar fluorite with an elongated hair like pyrite inclusion, complimented by a big shiny droplet of petroleum coating the dolostone.
Geology and Collecting: The Walworth Quarry works a stromatolite bearing Silurian dolostone. The mineralization occurs in a layer close to the surface of the bedrock in the high bench of the quarry. Like with the formation of Herkimer diamonds, the stromatolites provided space and protection for crystals to form in vugs.
The mineralogy of the locality is fairly simple with the only collectible minerals present in abundance being fluorite, dolomite, calcite, sphalerite, celestine, and gypsum var. selenite.
Before you Visit: The quarry does not have an official page for the open house, but usually it takes place on the second weekend of October. Arrive at the quarry early- 6:45 AM to register for the dig. Hard Hat and protective gear required for this location. Check local Northeast mineral club pages for more info.
Show up to the quarry to register for the dig at 6:45AM. Once registered, the rules will be explained and you will be lead to the site. The dig ends at noon. This rock works similarly to the dolostone to the east in which Herkimer diamonds are mined, meaning it is extremely hard. Bring a crack hammer, chisels, wedges, and a sledgehammer. Use flat chisels or wedges to work the cracks in rocks. Power tools are welcome at this quarry.
The best technique for splitting large boulders is feathering and wedging using a hammer drill to drill holes for wedges. A gas rock saw is also an extremely useful tool for extracting difficult specimens by slicing them out of the rock.
PPE is required on this dig. Bring a hard hat, steel toed boots, safety goggles, and gloves. The former three are a requirement. Remember also to bring plenty of water as well as snacks. There are restrooms on site but it is far away, near the entrance.
Special Thanks to The Dolomite Group for allowing the special privilege of mineral collecting in their quarries.
Sources:
https://www.mindat.org/loc-18146.html
http://fredmhaynes.com/2016/10/14/walworth-quarry-open-house/