Black Onyx The Majestic Black Gem Stone

Onyx is a variety of cryptocrystalline formed from quartz. Onyx stones are easily identified by the various bands of color present in the stone. These color bands can occur in any shade, except for blue and purple. On an average, onyx stones usually contain bands that are white, brown and tan in color.

The name comes from the Greek word onyx which means nail of a finger or claw. Legend says that one day while Venus was sleeping Eros/Cupid cut her fingernails and left the clippings scattered on the ground. Because no part of a heavenly body can die, the gods turned them into stone which later became known as onyx.

Originally, almost all colors of chalcedony from white to dark brown and black were called onyx (SiO2 with impurities). Today when we think of onyx we often preface the word with black to distinguish it from other varieties of onyx that come in white, reddish brown, brown and banded. A variety of onyx that is reddish brown with white and lighter reddish bands is known as sardonyx.


Physical Properties of Onyx :-

Onyx is a form of chalcedony, part of the quartz group. Like the other stones in the chalcedony family, onyx has a smooth, waxy luster. Onyx can be found in a wide range of colors, often layered.

Specific Gravity : 2.58 - 2.64
Refractive Index : 1.55 - 1.54
Hardness : 6.5 - 7.0 on Moh's scale


Chemical Properties of Onyx :-

Formula : SiO2
Elements : Si and O


Uses of Onyx :-

Black Onyx is often used as a backdrop in jewelry, such as cameos. It is also used as cabochons and as a building material. Onyx marble has excellent uses. Onyx marble is used most often as a fireplace surround; bar top, or as a small island as it transmits light.Careful consideration is required when using onyx marble at your residential area.

Onyx could also used for novelty items such as vases, urns, wine goblets, lamps and bowls. It really works wonderful where you could accent the stone and use under lighting or backlighting to draw attention of its transparent qualities. Onyx marble could be purchased in tile shape or in large slabs for a versatile look and feel.

Black and colored onyx is normally dyed. Onyx is easily dyed, so beware of the more "abnormal" looking onyx colors, such as bright blue, etc. Onyx with red and white bands is sometimes called as "Sardonyx". Onyx is the black selection of agate. However some parts of onyx are more or less translucent. This is why it is frequently heated to emphasize the intensity of its color.


Care onyx:-

Onyx is formed by the deposition of silica in gas cavities in lava, which results in the distinctive bands or stripes we see in the stone. They come in varied shades of red, orange, and brown, which often alternate with striking bands of white. The banding in onyx is straight, and is either brown or black and white, while curved bands occur in the variety of quartz known as agate.