Sphalerite (Twinned!) on Dolomite
Old Tri-State Mining District, Treece, Kansas, USA
Cabinet, 15.5 x 11.5 x 4.6 cm
Ex. Dr. Peter Bancroft
This is absolutely one of the nicest specimens I have seen from this venerable old mining district. If I had to guess based on past experience driving through the midwest, I'd guess it to be from the Cherokee Mine. A huge, coal-black, doubly-terminated, twinned crystal of sphalerite, over 2 INCHES or 5 CM in length, is aesthetically perched on a matrix! The matirx is not your usual rock, but rather is cyrstallized, made up of saddle-shaped crystals of dolomite to 1.0 cm across, upon which are scattered iridescent crystals of chalcopyrite. Considering that this locality has been closed for going on 40-plus years, this is indeed a special specimen!