Calcite

I bought this piece from my dear friend Frank Hissong (RIP) in 2010. These are rather large crystals for Banana Slide (2.8cm across) and the largest is twinned. Classic prismatic form and iron staining. An unusual crystal on the back side is lenticulated and twinned. Ex Hissong, Ex Krasnov.

Locality: Banana Slide, Florence Mine, Egremont, England

Composition: calcium carbonate