Hercules Mine (Negra Mine), La Negra, Mun. Sierra Mojada, Coahuila, Mexico
Glassy, gem-like Calcite scalenohedrons richly and aesthetically cover a bit of matrix on this beautiful Calcite specimen from this little-known Mexican iron mine. The largest crystal measures 30 x 18 mm, and is doubly terminated and twinned, like many of the Calcites on this specimen. They remind me of some of the great, old English Calcite, and are damage free. Very difficult to photograph, because the Calcite is so glassy! Formerly in the collection of Francisco Aguilera, a miner at the Hercules Mine, who self collected it in 1992. I acquired it for my collection in December 1992 during my first trip to the area.
ex. Bob Griffis collection