Onyx is the birthstone for Leos and the anniversary gemstone for the 7th year of marriage.
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. Ornamental materials were once mined in that area and it was an active center for trading various stones.
Onyx were used widely in the past as bases and handles for gold items, as well as for stone inlay work. Onyx seals were very popular with the Romans, who carved the pattern of the seal in negative relief to give a raised point. They often used stones with several layers, each of a different color, which were then individually carved to produce a different pattern each year. They originally used the onyx name for a variety of marble having white and yellow veins.
Onyx is the Greek word for “claw” or “fingernail” because these veins resemble the colors of a fingernail. The marble is still called “onyx marble,” being less valuable and softer than onyx which has a hardness rating of 7. Onyx was also traditionally used for carving cameo brooches.