A Stunning Large Malachite Rough
A large Malachie rough weighing 5693 grams submitted at GSI laboratory for testing. Image @ GSI
Malachite is a copper carbonate hydroxide mineral, with the formula Cu2CO3(OH)2. It is typically an ornamental material used for carvings and beads and can range in size from millimeters to specimens weighing pounds. A bright green color with light green streak has been suitable for mineral pigment in green paints since antiquity, decorative vase, ornamental stone, and gemstone. The presence of malachite is an excellent surface indicator for copper exploration.
Testing such large samples requires techniques and experience and GSI has developed techniques for testing such large samples. Recently, GSI Jaipur received a large green gem rough specimen submitted for identification, weighing 5693 grams. The specimen showed typical botryoidal structure with deep saturated green characteristic banding sufficient for identification of Malachite. Further, visual identification of Malachite confirmed with the help of laser Raman spectroscopy & energy dispersive x-ray fluorescence spectroscopy.
Malachite occurs as a common secondary mineral in the oxidation zone of copper ore deposits and can be an ore of copper. From the ornamental point of view the majority of Malachite rough comes from the Democratic Republic of the Congo (formerly Zaire), Namibia, Russia and the American Southwest.
The Hope Diamond and it’s famous red fluorescence caused by boron impurities.Image @ Smithsonian Institution
A large Malachite rough displaying botryoidal growth like a bunch of grapes. Image @ GSI