Sphalerite on Siderite drill bit twin A beautiful example of Feldspar

A beautiful example of Feldspar from Colorado

This is more than just a “black” rock just based upon its visceral beauty

hence the reduced priced

Specimen # BOL711B34

and one of the best pieces from the find that I've handled

Sphalerite on Siderite drill bit twin A beautiful example of FeldsparFrom my own personal collection, this cabinet sized display specimen is a quintessential Gilman sulfide carbonate association piece. Several remarkably sharp AND lustrous crystals of jet black Sphalerite with notably SMOOTH faces hardly any striations at all on many faces are gently intermixed and sitting atop a crystallized plate of soft beige cream colored compressed rhombohedra or discs of Siderite. The piece was mined in 1978, and I actually