Rebecca Zemans Jewelry Blog — lava

Onyx, our alternative birthstone of the month, is a variety of microcrystalline quartz, called chalcedony and found worldwide. Onyx was used in Egypt as early as the Second Dynasty to make utilitarian items such as bowls. Today it is often used for ornamental carvings and jewelry. Onyx jewelry is commonly found with cut cabochons or beads. The piece we made with onyx features a faceted cut version.  The onyx is formed by deposits of silica in gas cavities found in lava and measures 7 on the Mohs Scale of Hardness. Because of the environment where the stone is formed, the...