Calcite

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The Mineralogical Museum, University of Delaware

0 for sale

Calcite "butterfly twin," 10.8 cm, from Egremont, West Cumberland Iron Field, Cumbria, England. In the late 19th and early 20th centuries the West Cumberland Iron Field was one of the world’s most prolific mineral localities, producing beautiful barite, fluorite and calcite specimens by the thousands. Fine calcite was particularly abundant in the mines around Egremont, where twins like this one were well known from the Gillfoot mine—though most labels simply say "Egremont."