Biehlite (Ref: 6041)

I have mentioned earlier that the José Maria Patoni Mine in the Mexican state of Durango is known for its Calcite in optical quality, transparency/translucency of the crystals, and the crystallographic complexity of its crystals. And this specimen shows a completely different crystal form of Calcite. The slightly elongated scalenohedrons are not pointy but a bit stubby rounded although with excellent terminal faces, and the large crystals reach 4.6 cm in length. While color and luster are almost identical, the translucency of the crystals is significantly better. Despite a minimal chip and the imprint of a crystal on the back, this is a very unusual Calcite specimen that was obviously collected before 1960.