Datolite

Unknown Owner

A cut and polished one half of a datolite nodule. Nice color on this one. From the 11th level of the mine.The Quincy Mine in Houghton County, Michigan, was one of the most important copper mines in the Keweenaw Peninsula and operated from 1846 until 1945. The mine worked rich deposits of native copper found in fissure veins cutting basalt flows of the Portage Lake Lava Series. In addition to copper, the mine is well known among mineral collectors for datolite, a calcium boron silicate mineral that occurs in cavities within the volcanic rock. Datolite from the Quincy Mine commonly forms rounded nodules and botryoidal masses, often showing pink to pale color and sometimes containing inclusions of native copper. These specimens are considered classic minerals from the Keweenaw copper district.