Sphalerite with Quartz

Hard to photograph, and better in person, this attractive three-dimensional “mound” of black “Marmatite” Sphalerite is comprised of sharp, semi-lustrous, well-formed dodecahedral crystals which are associated with a few gemmy prismatic Quartz crystals. Excellent for the locality, and better than most I have seen from the mine.

The Black Cloud was one of the most famous specimen producing locales in Leadville and was one of the last operating mines in Colorado when it closed in 1999. The Leadville mining district was the most productive silver-mining region in Colorado. As of 1963 the cumulative production of the area was 240 million troy ounces of Silver = $6.6 billion at today’s prices.

Ex. Richard A. Kosnar collection

Specimen# CO712B49