Tyuyamunite, Calcite

This specimen features sparkly, canary-yellow, platy microcrystals of the rare uranium oxide mineral, tyuyamunite, scattered across the surface of a cluster of sharp, brown, doubly-terminated calcite crystals. The specimen originates from the Dandy Mine, located in Granite County, Montana. Though primarily a gold mine, the Dandy Mine is also known for producing secondary uranium minerals like tyuyamunite, which can be found in combination with calcite on rare occasions.