Black Onyx is the anniversary gemstone for the 10th year of marriage. Onyx is a variety of the microcrystalline quartz, called chalcedony. The name “chalcedony” comes from Calcedon or Calchedon, an ancient port on the Sea of Marmara in Asia Minor. ... Onyx was also traditionally used for carving cameo brooches.

Weight : 23.3 grams