Onyx is a cryptocrystalline form of quartz. The colors of its bands range from white to almost every color (save some shades, such as Purple or Blue.) Commonly, specimens of onyx available contain bands of colors of white, tan, and brown. Sardonyx is a variant in which the colored bands are sard (shades of red) rather than black. Pure black Onyx is common, and perhaps the most famous variety, but not as common as Onyx with banded colors. Onyx may refer to: Onyx, a black mineral Onyx (PYc-5) a United States Navy patrol vessel of the mid 20th century. ... A cryptocrystal is a rock whose texture is so finely crystalline—that is, made up of such minute crystals—that its crystalline nature is only vaguely revealed even in a thin section by transmitted polarized light. ... For other uses, see Quartz (disambiguation). ... Sard is a reddish-brown chalcedony, SiO2, much used by the ancients as a gemstone. ...

The agate-like sardonyx (banded agate). The specimen is 2.5 cm (1 inch) wide.

It is usually cut as a cabochon, or into beads, and is also used for intaglios and cameos, where the bands make the image contrast with the ground. Some onyx is natural but much is produced by the staining of agate. Image File history File links Download high resolution version (750x626, 88 KB) Banded agate. ... Image File history File links Download high resolution version (750x626, 88 KB) Banded agate. ... A cabochon or cabouchon is a gemstone which has been shaped and polished as opposed to facetted. ... Intaglio refers to incised (negative) image-making, and is the opposite of cameo. ... 2002 Lincoln cent, obverse, proof with cameo Cameo is a method of carving, or an item of jewelry made in this manner. ... For other uses, see Agate (disambiguation). ...

The name has sometimes been used, incorrectly, to label other banded lapidary materials, such as banded calcite found in Mexico, Pakistan, and other places, and often carved, polished and sold. This material is much softer than true onyx, and much more readily available. The majority of carved items sold as 'Onyx' today are this carbonate material. [1] A lapidary (the word means concerned with stones) is an artisan who practices the craft of working, forming and finishing stone, mineral, gemstones, and other suitably durable materials (amber, shell, jet, pearl, copal, coral, horn and bone, glass and other synthetics) into functional and/or decorative, even wearable, items (e. ... Doubly refracting Calcite from Iceberg claim, Dixon, New Mexico. ...

R-phrases R42 R43 R49 S-phrases S22 S36 S37 S45 S53 Flash point non-flammable Supplementary data page Structure and properties n, εr, etc. ... The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. ... Relative density (also known as specific gravity) is a measure of the density of a material. ... The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ... A calcite crystal laid upon a paper with some letters showing the double refraction Birefringence, or double refraction, is the decomposition of a ray of light into two rays (the ordinary ray and the extraordinary ray) when it passes through certain types of material, such as calcite crystals, depending on...

Culture and historical usage

Onyx from Australia

Onyx from Brazil

Image File history File links Metadata No higher resolution available. ... Image File history File links Metadata No higher resolution available. ... Image File history File links Size of this preview: 589 × 600 pixelsFull resolution (599 × 610 pixels, file size: 38 KB, MIME type: image/jpeg) onyks, pochodzenie Brazylia; autor zdjęcia Grzegorz Framski File historyClick on a date/time to view the file as it appeared at that time. ... Image File history File links Size of this preview: 589 × 600 pixelsFull resolution (599 × 610 pixels, file size: 38 KB, MIME type: image/jpeg) onyks, pochodzenie Brazylia; autor zdjęcia Grzegorz Framski File historyClick on a date/time to view the file as it appeared at that time. ...

History

Onyx is originally an Assyrian word meaning ring, and so could refer to anything used for making rings.

In the Dreamlands, a fictional location in the works of the author H. P. Lovecraft, the palaces of Kadath are built of onyx. The Dreamlands is a fictional location in the Dream Cycle of H. P. Lovecraft. ... H. P. Lovecraft Howard Phillips Lovecraft (August 20, 1890–March 15, 1937) was an American author of fantasy and horror fiction, noted for giving horror stories a science fiction framework. ...

Black Onyx with bands of colors.

Image File history File links Metadata No higher resolution available. ... Image File history File links Metadata No higher resolution available. ...

Astrological Relations

The onyx is the stone for the zodiac sign, Leo. It can be many different colors, but the ones with the reddish brown color is the preferred type. Onyx is said to banish grief and bring fortune to the possessor of it. It's said to also bring recognition of personal strengths.

Precautions

Onyx should not be cleaned with an ultrasonic cleaner or cleaned with abrasive or ammonia based cleaner as using such types can cause discoloration of the stone.

References

• http://www.gemstone.org/gem-by-gem/english/onyx.html
• http://www.mindat.org/min-2999.html

See also

Look up onyx in Wiktionary, the free dictionary.

Wikimedia Commons has media related to:

Onyx

• List of minerals