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Moijey Fine Jewelry & Diamonds Blog » Birthstone
Brilliantly Layered Sardonyx
Originally published on August 25th, 2017 Updated on April 10th, 2020 August's third birthstone is a unique gemstone, but it is readily available. The third gem is called Sardonyx, a variety of chalcedony. Chalcedony is a cryptocrystalline quartz aggregate with an anamorphic crystal composition. Millions of tiny quartz crystals build the structure; the crystals are so small that a special microscope is needed to see each crystal. Sardonyx is a variety of cryptocrystalline quartz with alternating layers of either black or white bands with reddish-brown layers of sard. The picture above from the Smithsonian provides excellent examples of Sardonyx. What...