Natural Big Cluster with Sphalerite and Quartz from Bulgaria 1038g

A broad plate split between two textures. Black sphalerite covers roughly half the face in rounded, knobbly masses with a dull to submetallic surface, and the rest is a pale olive-cream crust of fine crystal. Growing out of both, and running right across the boundary between them, are slender white quartz needles, some standing singly, others in small radiating sprays, and it is these that tie the two halves together. The needles show at their clearest against the black.

Slender, needle-like quartz of this kind grows quickly, which is why the crystals stay thin instead of thickening into the blocky prisms more usual in the same veins. From the Bulgarian lead-zinc field in the Rhodope Mountains. Untreated. Sphalerite is 3.5 to 4 on the Mohs scale and quartz 7, and the fine needles are the fragile part. At 160x130mm and just over a kilo this is a display plate.

Natural sphalerite with quartz needles, Bulgaria, single piece.