Chalcocite, Calcite, Quartz

Here is an unusual specimen! It is a portion of a brecciated vein from an old copper mine on the Canadian side of Lake Superior. It is a breccia cemented with white drusy quartz crystals, showing lots of quartz crystal-lined open spaces between the breccia fragments. In the open spaces, on the quartz are small chalcocite crystals, partially altered to malachite plus sharp, creamy white scalenohedral crystals of calcite. Really nice!