Once red, then green, now blueA stunning pair of crystals reveals some of the complex changes that h
Once red, then green, now blueA stunning pair of crystals reveals some of the complex changes that happen in ore deposits as they get uncovered by erosion and their primary minerals (usually dull grey or silvery sulphides) are gradually altered into a succession of secondary ones as the ore is percolated by circulating waters of varied chemistry that move through all the surface layers of our planet. The 1.4 x 1.3 x 0.8 cm piece from France started as the copper oxide mineral Cuprite (see http://bit.ly/1Cbe5f9 and http://bit.ly/1AjbRrW) as oxygenated fluids first altered it, followed by a succession of copper carbonates. It first turned into green Malachite (with some remnants still visible) before changing again into blue Azurite. The final product retains the shape and crystal habit of the original mineral, a process named after the Greek for fake shape and known as pseudomorphosis.LozImage credit: Joe Budd/Rob Lavinsky/iRocks.com -- source link
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