The rare mineral Chalcotrichite is a variety of Cuprite, having the same chemical composition (Cu₂O) but a different physical structure; the atoms are stacked and configured uniquely, making for distinctly different crystal formations than that of Cuprite. 

The crystal system for Chalcotrichite is isometric, its crystals composed of dense mats of hair-like or needle-like fibers. In fact, the Greek words to identify this mineral are translated as “hairy copper.” Known to miners as “wire copper” and “plush copper ore,” this striking mineral is typically red with a silky (or hairy?) luster, often occurring with Copper, Calcite, Cuprite, Malachite and Quartz to name a few.

Chalcotrichite is limited to a few localities with quality specimens found in England, Germany, Namibia and the USA (Arizona).