Dolomite coated by Galena with Sphalerite

Item Description

The Black Cloud Mine in Leadville, Colorado was one of the great specimen-producing localities in the district during the latter half of the 20th century. It will probably be best remembered for its superb golden Baryte crystals, but it produced a good number of other minerals during the time it was in operation. This piece is a fairly uncommon specimen of Dolomite featuring dozens if not hundreds of cream colored rhombs, forming attractive aggregates, with individual rhombs measuring up to 7 mm, that have a light "dusting" of silvery-grey Galena on the surface. The reverse side of the specimen hosts black Sphalerite with minor accenting Galena. No major damage, only one scar on the corner where the piece was removed from the pocket wall. A fairly hard to find specimen, not just for the locality, but the species as well, since there were not many good display specimens of Dolomite to come out of this mine.
From the collection of Richard ("Rich") Andrew Kosnar (1946-2007), the well-known mineral dealer and collector from Colorado, who was the namesake for the phosphate species Kosnarite. Rich built a large suite of minerals from Colorado during his life, and would often visit the mines / miners personally to acquire specimens all over the state.