Quartz ''cast'' after Calcite

Item Description

These iconic specimens from just outside the town of Ouray in the San Juan Mountains of Colorado are some of the most classic Quartz after Calcite "casts" (epimorphs/perimorphs) from any world locality. This wonderful full miniature sized specimen is a fantastic example showing the perfect scalenohedral form of the previous Calcite crystals which were replaced / coated by very small, almost "sugary", gem quality, colorless Quartz crystals. The Calcite crystals were then dissolved away by a solution that entered the pocket at a later date, leaving behind only the thin Quartz crystal "crust". A wonderful specimen from a district that produced some of the most classic "casts" from all of Colorado.
From the collection of Colorado mining legend, Dave Bergman. Dave is now retired, but among other things, he was the foreman and primary person in charge of recovering specimens at the famous Sweet Home Mine near Alma, Colorado during the late 1970s. He is also the maternal grandfather of Brian Kosnar. See Dave's photo mining at the Sweet Home on page 58 of Peter Bancroft's book "Gem and Crystal Treasures".