EZR99AP2: Scalenohedral crystals of Calcite, one of them clearly dominant, accompanied by leafy aggregates of Copper surrounding the Calcite crystals externally, but with the particularity that other Copper crystals are included within the scalenohedrons of Calcite, giving them the reddish color so characteristic of this type of specimen, an American classic.

Quincy Mine is located in the city of Hancock, Houghton County, Michigan State, United States. It forms part of the historic copper mining district of Michigan’s Upper Peninsula, one of the most important regions in the world for native copper production during the 19th and early 20th centuries. The mine became known as 'Old Reliable' because of its long and steady copper output.

Geologically, the mineralization belongs to the Lake Superior copper district, characterized by native copper deposits associated with Proterozoic basaltic volcanic rocks of the Keweenawan Group. Copper occurs filling amygdaloidal cavities and fractures within basalts and volcanic conglomerates, commonly associated with secondary minerals such as Calcite, Epidote, Prehnite, and Datolite.
Quincy Mine, Hancock, Houghton County, Michigan  USA

Specimen size: 6.1 × 4.8 × 2.3 cm = 2.40” × 1.89” × 0.91”

Main crystal size: 4 × 2.1 cm = 1.57” × 0.83”