Proustite from Chile, Atacama, Chañarcillo Mining District

This is a chunky, old-time Chañarcillo proustite: a solid bouquet of thick, prismatic crystals growing in near-parallel arrangement, fanning outward from the base like a closed fist of blood-red blades. The largest crystals measure 3 to 4 cm, which is exceptionally large for Chañarcillo proustite. They are also thick and three-dimensional rather than thin or flattened, and at 202 grams the piece has impressive heft for its size. Backlit, the interiors glow a deep, saturated cherry red with true gemmy translucency in the larger crystals. The prism faces show the strong adamantine luster that makes this species so striking. The surfaces also carry the steely, silvery-gray patina characteristic of old proustite specimens. Here it gives a two-tone look, gunmetal over ruby red, that many old-school collectors prefer. The terminations along the top are naturally etched and frosted, which contrasts with the slick, striated prism faces below. A cluster of small, sharp secondary crystals nestles in a pocket near the center. The specimen is complete all the way around, solid, and displays well from several angles.

Chañarcillo is the classic locality for proustite and the benchmark for the species. It was one of the richest silver districts of the 19th century, and its ruby silver specimens went to the great European cabinets of that era. The mines have long been inactive, so nearly every good Chañarcillo proustite available today comes from an older collection. Crystals of this size are especially hard to find, which makes this a standout piece for an advanced collection.

As with all proustite, keep this specimen out of direct and prolonged light to slow further darkening.