Quartz cast after Anhydrite (Ken Roberts Coll.)

Item Description

This Ouray District mine in the San Juans is famous for outstanding quartz pseudomorphs and this is surely one of the most exotic looking large specimens imaginable. These specimens have been labeled as being quartz after baryte, but given the fact that baryte is chemically inert and nearly impossible to dissolve, it is most likely that these pseudomorphs/epimorphs/perimorphs/"casts" are actually quartz replacing anhydrite. It has been reported that Dr. Virgil Lueth or New Mexico Tech concludes from studies (as-yet unpublished paper 4/2011) that these and all San Juan quartz epimorphs apparently after baryte are in fact after anhydrite. See extraLapis English No. 15, p.44 for Virgil Lueth's analysis that these are casts after anhydrite. This remarkable 360-degree specimen is a striking pseudomorph/cast consisting of a large blocky tabular crystal of what was once anhydrite now replaced by sharp, lustrous quartz crystals. Partial preferential dissolution of the quartz points on one side has left behind a fantastic quartz crystal "bridge" above the eerie looking etched quartz on the interior sides and the starkly contrasting distinctive redddish-brown iron oxide coatings, that are characteristic of the locale. A classic, extraordinary and surreal large quartz pseudo from the Ken Roberts Pseudomorph Collection. Valued at $1500-2000. RARELY on the market, these are so desirable.