Fossil Coral 12mm Coin 8-Inch Blue Chalcedony It occurs with wave-like bands

It occurs with wave-like bands of charcoal gray

which may form green stains or specks on Azurite crystals or aggregates

Trace amounts of iron can also affect the hue

Its bright green coloration is due to traces of chromium

Hydrogrossular garnet is an especially rare gemstone

Fossil Coral 12mm Coin 8-Inch Blue Chalcedony It occurs with wave-like bandsFossil Coral is the prehistoric fossilized remains of the invertebrate reef builders that live in tropical oceans. Silica rich waters create hardened deposits that preserve coral skeletons, resulting in fossils that are chalk white, tan, gray, and brown as well as pink, red and yellow orange.