onyx

A chalcedony that occurs in bands of different colors and is used as a gemstone, especially in cameos and intaglios.

[Middle English onix, from Old French, from Latin onyx, from Greek onux, nail, onyx.]

Banded chalcedonic quartz, in which the bands are straight and parallel, rather than curved, as in agate. Unfortunately, in the colored-stone trade, gray chalcedony dyed in various solid colors such as black, blue, and green is called onyx, with the color used as a prefix. Because the color is permanent, the fact that it is the result of dyeing is seldom mentioned.

The natural colors of true onyx are usually red or brown with white, although black is occasionally encountered as one of the colors. When the colors are red-brown with white or black, the material is known as sardonyx; this is the only kind commonly used as a gemstone. Its most familiar gem use is in cameos and intaglios. See also Cameo; Chalcedony.

A family of graphics supercomputers from SGI that use the MIPS R10000 CPU and range from single-processor workstations to rack-mounted systems with 128 CPUs. They use SGI's InfiniteReality graphics subsystem which processes geometry, imaging and video data in real time.

Download Computer Desktop Encyclopedia to your iPhone/iTouch

adjective

Of the darkest achromatic visual value: black, ebon, ebony, inky, jet¹, jetty, pitch-black, pitchy, sable, sooty. See colors/colorless.

For more information on onyx, visit Britannica.com.

A banded, varicolored form of quartz, closely related to agate; cut into slabs, polished, and used for decorative building stone.

Onyx Acceptance Corporation

This article is about the mineral. For other uses, see Onyx (disambiguation).

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.

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.

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]

Technical details

Chemical composition and name	SiO2 - Silicon dioxide
Hardness (Mohs scale)	7
Specific gravity	2.65 - 2.667
Refractive index (R.I.)	1.543 - 1.552 to 1.545 - 1.554
Birefringence	0.009
Optic sign	Positive
Optical character	Uniaxial

Contents 1 Etymology 2 Historical usage 3 References 4 See also

Etymology

Onyx comes through Latin from the Greek onyx meaning 'claw' or 'fingernail'. With its fleshtone color, onyx can be said to resemble a fingernail. The English word 'nail' is cognate with the Greek word.^[2]

Historical usage

Onyx from Australia.

Onyx from Brazil.

The Beinecke Rare Book and Manuscript Library at Yale University was originally planned to be coated in green onyx. However, there wasn't sufficient green onyx in the world to build such a structure, so that the designers used marble. Onyx was known to the ancient Greeks and Romans.^[3] Use of sardonyx appears in the art of Minoan Crete, notably from the archaeological recoveries at Knossos.^[4] Onyx was used in Egypt as early as the Second Dynasty to make bowls and other pottery items.^[5] It is also mentioned in Exodus 25.

Black onyx with bands of colors.

References

1. ^ Profile of onyx
2. ^ http://www.etymonline.com/index.php?term=onyx
3. ^ International Colored Gemstone Association: Onyx
4. ^ C. Michael Hogan (2007) Knossos fieldnotes, The Modern Antiquarian
5. ^ Mary Winearls Porter, What Rome was Built with: A Description of the Stones Employed, 1907, H. Frowde, Rome, 108 pages

See also

Look up onyx in Wiktionary, the free dictionary.

Wikimedia Commons has media related to: Onyx

• List of minerals

v • d • e Jewellery materials Precious metals: Gold · Palladium · Platinum · Rhodium · Silver Precious metal alloys: Colored gold · Electrum · Platinum sterling · Sterling silver Base metals/alloys: Brass · Bronze · Copper · Stainless steel Mineral Gemstones: Aventurine · Agate · Alexandrite · Amethyst · Aquamarine · Carnelian · Citrine · Diamond · Emerald · Garnet · Jade · Jasper · Malachite · Lapis lazuli · Moonstone · Onyx · Opal · Peridot · Quartz · Ruby · Sapphire · Sodalite · Sunstone · Tanzanite · Tiger's Eye · Topaz Organic Gemstones: Amber · Copal · Coral · Jet · Pearl

v • d • e Silica minerals Crystalline Coesite · Cristobalite · Moganite · Quartz · Stishovite · Tridymite Cryptocrystalline Chalcedony · Chert · Flint · Jasper Amorphous Fulgurite · Lechatelierite · Opal Miscellaneous Quartzite · Tiger's eye · Vitreous quartzite Notable varieties Chalcedony Agate · Carnelian · Chrome chalcedony · Chrysoprase · Heliotrope · Moss agate · Lake Superior agate · Onyx Jasper / Chert Mozarkite · Orbicular jasper Opal Fiorite · Geyserite Quartz Amethyst · Ametrine · Citrine · Milky quartz · Rose quartz · Smoky quartz · Shocked quartz

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
n. - onyks

Nederlands (Dutch)
onyx, steensoort

Français (French)
n. - onyx

Deutsch (German)
n. - Onyx

Ελληνική (Greek)
n. - (ορυκτολ.) όνυχας

Italiano (Italian)
onice

Português (Portuguese)
n. - ônix (m)

Русский (Russian)
оникс

Español (Spanish)
n. - ónice, ónix

Svenska (Swedish)
n. - onyx

中文（简体）(Chinese (Simplified))
缟玛瑙

中文（繁體）(Chinese (Traditional))
n. - 縞瑪瑙

한국어 (Korean)
n. - (줄무늬가 있는)마노, 손,발톱

日本語 (Japanese)
n. - 縞瑪瑙, オニキス, 縞大理石
adj. - 漆黒の

العربيه (Arabic)
‏(الاسم) العقيق اليماني‏

עברית (Hebrew)
n. - ‮שוהם, קוורץ צבעוני, אנך‬

If you are unable to view some languages clearly, click here.

To select your translation preferences click here.