Helvine with Quartz

Item Description

A rarely seen association specimen from the large Huanggang Fe-Sn Deposit in far northern China. This small cabinet specimen hosts a sharp, lustrous, well-formed, tetrahedral, golden-brown crystal group of Helvine measuring 6 mm, associated with semi-"cactus"-esque, gemmy, colorless, prismatic Quartz crystals measuring up to 5.2 cm long, sitting on a matrix of chalky white rhombic Calcite (some of which have formed partially "hollow" crystals - casts(?)) sitting on a matrix of dark grey-black Magnetite. I can see a tiny bit of muted blue-green colored "Chlorite" on underside of the piece as well. It should be noted that some of these Helvine crystals have been analyzed, and show chemical variations (manganese transitioning to zinc) to the point where they are actually Genthelvite, but this piece has not been analyzed, so I don't know if it's only Helvine or if both species are present. My favorite aspect of the piece are the Quartz crystals, which are better than most other pieces of featuring Helvine that I've seen from this mine. No major damage, and very attractive up close and on display on a shelf in a mineral case. From the collection of Brian Kosnar.