Turquoise psm after Bone (Odontolite) - Yarvicoya Mine, Oruro, Oruro Dept., Bolivia
Occasionally, in arid areas in/near copper deposits, animals perish and their bones are replaced by copper minerals from the water running
through the veins and cracks in the rocks over thousands of years - a
phenomenon known from a few places around the world. Here, in this case
the replacement is by turquoise of carving grade! This rare pseudomorph
of turquoise after bone (odontolite) exhibits a pleasing light teal-blue
color. It is apparently the jawbone of a mammal, probably dated around
20-40,000 years old.
Central Mine, Central, Keweenaw Co., Michigan, USA
Found these sitting out on the surface yesterday.Met some old hounds who suggested that the Cliff mine up on top and Nassau pile of the Calidonia mine were also good spots. One of them also said that if you can get into the old mines, there might even be bits of crystalline copper (they mined by candlelight with hand tools in the 1850s and missed a bunch of stuff).