Gemstone :
Onyx

Birthstone Month :
Onyx is one of the gemstones associated with the month of December.

Zodiac :
Onyx is associated with the zodiac sign of Leo.

Chemical Symbol :
SiO2

Chemical Make-up :
Onyx is a Silicon Dioxide and is a member of the Chalcedony Quartz family.

History & Lore :
The name Onyx is a derivation of the Greek word 'onux', meaning “fingernail”.

Legend says that a sleeping Venus had her divine fingernails cut off with an arrowhead by Eros/Cupid. He left the clippings scattered on the sand below, which later turned to stone because the god's felt that no part of Venuses heavenly body should ever perish. Originally, in Greek times, almost all colors of Chalcedony from white to dark brown and black were labeled as Onyx. It was then later decided by the Ancient Romans that the term Onyx would only be used refer to the black and dark brown colored stones.

The reddish brown and white colored variety of Onyx, known as Sardonyx, was highly valued in Rome, particularly for seals, because it was said to never stick to wax. The Roman General Publius Cornelius Scipio was well-known for wearing Sardonyx jewelry.

The Ancient Romans associated Onyx with courage, and it was thought to be useful when defending oneself against criticism. It also is thought to have protective qualities, particularly when traveling. It is believed to bring about spiritual inspiration and to assist with keeping emotions and passions under control. It is also believed to help the wearer to change bad habits

Physically Onyx is believed to strengthen the heart, kidneys, nerves, hair, eyes and nails. It is also believed to relieve stress and neurological disorders, and to aid sleep.

Availability :
Onyx is readily available and priced moderately.

Sources :
Onyx deposits are found worldwide.

Evaluation :
Onyx is rated at 6.5 to 7 on Moh's Scale of Hardness and care should be taken to protect against chipping and scratching. Though Onyx is most commonly referenced with the color black, occasionally it is found exhibiting hues of reddish brown and white. This variety is known as Sardonyx. Black Onyx is a brownish- black to black opaque stone with a smooth, waxy luster. Not only is it readily available and affordable but its deep, dark, lustrous surface can display a striking contrast with other warm-colored gemstones, making it an excellent addition to a jewelry collection. In addition to this, Onyx can also display white bands or ribbons against a black background. When these layers are even, this type of Onyx will often be carved into cameos.

Common Cuts :
Onyx is most often found cut into smooth rounded cabochons. It can also be found as a backdrop in jewelry such as cameos.

Routine Enhancements :
All Black and colored Onyx that is commercially available today is either heat-treated or dyed to increase depth of color.

Care & Cleaning :
Onyx is best cleaned using warm soapy water and a soft brush. As with most gemstones, Onyx should be kept away from prolonged exposure to extremes of heat and household chemicals that can damage the stone. Onyx can chip or scratch relatively easily, so it should always be stored in a fabric-lined box away from other jewelry items.