This proustite is from the Uchucchacua Mine, Oyon Province, Lima Department of Peru.This Is a silver mine that contains 53 different minerals including the silver sulfide proustite. It contains elements Ag, As, and S. It is found in the oxidation zones of silver ore deposits. This specimen consists of a mixed quartz and sulfide matrix that is covered on the display side with druse quartz and proustite crystals. It has a reddish hue as is indicative of the name ruby silver which is often used to describe this mineral. This piece measures 1 1/4 x 1 x 9/16 or 32 x 25 x 14 mm. The proustite crystal is approximately 12 mm across.