Polybasite, Fresnillo Case Quarries Information
- Head east on Isinglass Hill Road for 0.7 miles.
- Turn right onto Thompson Hill Road for 0.8 miles
- Turn left onto East Cotton Hill Road for 0.2 miles
- Park underneath the power lines.
Get out of your car and hike up the hill underneath the power lines until you see a bunch of white quartz (part of the old quarry dumps) on your left. Head into the woods here. There are several prospects visible from just inside the woods.
Collecting is allowed by STATE PERMIT ONLY!
*** click here for driving directions via google maps ***
The principle mineral of interest at the Case Quarries is beryl, which is mostly a blue green to aqua, some are yellow. Not much is available in the quarries themselves, but there are numerous dumps at the three old quarries to sort through. Schorl, spessartine, columbite, and rare bismuth minerals are also available. Monazite-Ce, the rare mineral petscheckite (UFe(Nb,Ta)2O8 only the third discovery world-wide), and cordierite were recently reported. Much has been written about these little quarries. For details on history, a description, many specimen and site photos, see: