Ankerite and Marmatite

The Eagle Mine produced gold from 1879 to 1925 at which point lead and zinc were mined until 1984. The 24 level drift produced superb examples of Ankerite, and we might assume this specimen was found during that time. It exhibits wonderful jet black lustrous tetrahedral and twinned aggregates of Marmatite interlaced among buff to cream colored Ankerites. Ex Mike Wortham

Locality: Eagle Mine, near Gillman, Eagle County Colorado

Composition: calcium  iron  magnesium manganese carbonate and zinc iron sulfide