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.
The myth of the origin of onyx says that the goddess Venus was resting on the banks of the Indus River. As she slept, Cupid used the point of one of his enchanted arrows to give her a manicure. The parings of her nails then fell into the waters of the sacred river. Since the nails were of heavenly origin, they sank to the river bottom and were metamorphosed into onyx.
Onyx is a protective stone worn when facing adversaries in battles of conflicts of all kinds, or while hurrying down a dark street late at night. In classical ceremonial magic, the image of the head of the god Mars or a figure of the hero Hercules was engraved on onyx and carried for courage. Indians and Persians believed that wearing onyx protected them from the evil eye, and that placing onyx on the stomach of a pregnant woman in labor would reduce the labor pain and bring on earlier delivery.
Natural black onyx is rare, so the commercial black variety is usually agate that has been stained by the sugar-sulfuric acid treatment, soaked in sugar and then heated in sulfuric acid to carbonize the sugar. It may be banded or solid black.
Onyx can be found in Uruguay and bordering regions of Brazil, Afghanistan, India, Madagascar, Peru and the US. Baja California, and northwest Mexico were a major source for onyx until cheap imitations appeared on the market.
Caring for your Onyx Jewellery
The best way to clean an onyx is to wipe it clean with a moist cloth. It is not recommended to use any sort of ultrasonic cleaners or ammonia as the stones may be porous and therefore might absorb chemicals, even soap, which can build up inside the stone, causing discoloration.