Natural Sphalerite and Quartz Cluster Crystal from Bulgaria 198g

Slender quartz prisms scatter across the face of this piece in loose sprays and singles, colorless to milky white, each one sharply terminated and standing clear of a dark, granular groundmass of black sphalerite. The matrix beneath carries a greenish-grey cast where chlorite has coated it, so the effect is a bright white crystal pattern laid over near-black rock. A single small honey-brown crystal sits near the center where the sphalerite has grown thin enough to pass light.

Sphalerite crystallizes in the same veins as the quartz here, and where a crystal grows thin it lets light through with the amber-brown color that zinc sulfide gives. This piece comes from the Bulgarian lead-zinc deposits of the Rhodope Mountains. Untreated. Sphalerite is 3.5 to 4 on the Mohs scale and quartz 7, and at 105mm long with an open, well-covered face it displays best lying flat.

Natural sphalerite with quartz crystals, Bulgaria, single piece.