onyx

Onyx comes through Latin (of the same spelling), from the Ancient Greek {{lang|grc|ὄνυξ}} ({{transl|grc|onyx}}), meaning {{gloss|claw}} or {{gloss|fingernail}}. Onyx with pink and white bands can sometimes resemble a fingernail.{{cite web|url=http://www.etymonline.com/index.php?term=onyx|title=Online Etymology Dictionary|work=etymonline.com|access-date=22 August 2015}} The English word "nail" is cognate with the Greek word.

File:Red onyx - Handicraft.jpgs of red onyx, also called sardonyx]]

File:Black Onyx.jpg

Onyx is formed of chalcedony bands in alternating colors. It is cryptocrystalline, consisting of fine intergrowths of the silica minerals quartz and moganite. Its bands are parallel, unlike the more chaotic banding that often occurs in agates.{{cite book |last1=Assaad|first1=Fakhry A. |last2=LaMoreaux|first2=Philip E. Sr. |title=Field Methods for Geologists and Hydrogeologists |year=2004 |publisher=Springer-Verlag |location=Berlin, Heidelberg, New York |isbn=3-540-40882-7 |editor-last=Hughes|editor-first=Travis H. |page=8}}

Sardonyx is a variant in which the colored bands are sard (shades of red) rather than black. Black onyx is perhaps the most famous variety, but it is not as common as onyx with colored bands. Artificial treatments have been used since ancient times to produce the black color in "black onyx" and the reds and yellows in sardonyx. Most "black onyx" on the market is artificially colored.{{cite book |last=Sinkankas|first=John |title=Gemstones of North America |year=1959 |publisher=Van Nostrand |location=Princeton, New Jersey |page=316 |volume=1}}{{cite journal |title=The Manufacture of Gem Stones |journal=Scientific American |date=25 July 1874 |page=49 |publisher=Munn & Company |location=New York}}{{Better source needed|date=July 2024}}{{disputed inline|date=July 2024}}

The name has also commonly been used to label other banded materials, such as banded calcite found in Mexico, India, and other places, and often carved, polished, and sold. This material is much softer than true onyx and more readily available. The majority of carved items sold as "onyx" today are this carbonate material.{{cite web |url=http://www.mindat.org/min-2999.html |title=Onyx |publisher=mindat.org |access-date=22 August 2015}}{{cite book|last1=Hurlbut|first1=Cornelius S.|last2=Sharp|first2=W. Edwin|title=Dana's Minerals and How to Study Them|year=1998|publisher=Wiley|location=New York, New York|isbn=0-471-15677-9|page=[https://archive.org/details/danasmineralshow00hurl/page/200 200]|edition=4th|url-access=registration|url=https://archive.org/details/danasmineralshow00hurl/page/200}}

Artificial onyx types have also been produced from common chalcedony and plain agates. The first-century naturalist Pliny the Elder described these techniques used in Roman times.{{cite book|last=O'Donoghue|first=Michael|title=Synthetic, Imitation, and Treated Gemstones |year=1997 |publisher=Butterworth-Heinemann |location=Boston |isbn=0-7506-3173-2|pages=125–127}} Treatments for producing black and other colors include soaking or boiling chalcedony in sugar solutions, then treating with sulfuric or hydrochloric acid to carbonize sugars which had been absorbed into the top layers of the stone.{{cite book|last=Read|first=Peter G.|title=Gemmology|year=1999|publisher=Butterworth-Heinemann|location=Oxford |isbn=0-7506-4411-7|page=160}} These techniques are still used, as well as other dyeing treatments, and most so-called "black onyx" sold is artificially treated.{{cite book|last=Liddicoat|first=Richard Thomas|title=Handbook of Gem Identification |year=1987|publisher=Gemological Institute of America|location=Santa Monica, California |isbn=0-87311-012-9 |pages=158–160 |edition=12th}} In addition to dye treatments, heating and treatment with nitric acid have been used to lighten or eliminate undesirable colors.

Onyx can be found in various regions of the world, including Greece, Yemen, Uruguay, Argentina, Australia, Brazil, Canada, China, Czech Republic, Germany, Pakistan, India, Indonesia, Madagascar, Latin America, the UK, and various states in the US.

File:Kunsthistorisches Museum Vienna June 2006 031.jpg is a Roman cameo produced 9–12 AD and carved in a two-layered onyx gem (19 × 23 cm).]]

It has a long history of use for hardstone carving and jewelry, where it is usually cut as a cabochon or into beads. It has also been used for intaglio and hardstone cameo engraved gems, where the bands make the image contrast with the ground.{{cite book|last1=Kraus|first1=Edward Henry|last2=Slawson|first2=Chester Baker|title=Gems and Gem Materials|url=https://archive.org/details/in.ernet.dli.2015.280103|year=1947|publisher=McGraw-Hill|location=New York, New York|page=[https://archive.org/details/in.ernet.dli.2015.280103/page/n234 227]}} Some onyx is natural but much of the material in commerce is produced by the staining of agate.{{cite book|last1=Liddicoat|first1=Richard Thomas|last2=Copeland|first2=Lawrence L.|title=The Jewelers' Manual|year=1974|publisher=Gemological Institute of America|location=Los Angeles, California|page=87}}

Onyx was used in Egypt as early as the Second Dynasty to make bowls and other pottery items.{{cite book|last=Porter|first=Mary Winearls|author-link=Mary Winearls Porter|title=What Rome was Built with: A Description of the Stones Employed|url=https://archive.org/details/whatromewasbuilt00portiala|year=1907|publisher=H. Frowde|location=Rome|page=[https://archive.org/details/whatromewasbuilt00portiala/page/108 108]}} Use of sardonyx appears in the art of Minoan Crete, notably from the archaeological recoveries at Knossos.C. Michael Hogan (2007) [http://www.themodernantiquarian.com/site/10854/knossos.html#fieldnotes Knossos fieldnotes, The Modern Antiquarian]

Brazilian green onyx was often used as plinths for art deco sculptures created in the 1920s and 1930s. The German sculptor Ferdinand Preiss used Brazilian green onyx for the base on the majority of his chryselephantine sculptures.{{cite web|title=Ferdinand Preiss|url=http://www.hickmet.com/artist/fritz-ferdinand-preiss|website=Hickmet.com|access-date=18 June 2015}} Green onyx was also used for trays and pin dishes – produced mainly in Austria – often with small bronze animals or figures attached.{{cite web |title=Lot 419, Schmidt-Hofer, Otto, 1873-1925 (Germany)|website=ArtValue.com| url=http://www.artvalue.com/auctionresult--schmidt-hofer-otto-1873-1925-g-art-deco-skulptur-in-form-eine-2160708.htm}}

Onyx is mentioned in the Bible many times.{{cite web|url=https://www.biblegateway.com/quicksearch/?quicksearch=Onyx&version=DRA&resultspp=25|title=BibleGateway|work=biblegateway.com|access-date=22 August 2015}} Sardonyx (onyx in which white layers alternate with sard – a brownish color) is mentioned in the Bible as well.{{cite web|url=https://www.biblegateway.com/quicksearch/?quicksearch=sardOnyx&qs_version=DRA|title=BibleGateway|work=biblegateway.com|access-date=22 August 2015}}

Onyx was known to the Ancient Greeks and Romans.{{cite web|url=http://www.gemstone.org/gem-by-gem/english/onyx.html|title=Onyx|author=Administrator|work=gemstone.org|access-date=22 August 2015}} The first-century naturalist Pliny the Elder described both types of onyx and various artificial treatment techniques in his Naturalis Historia.

Slabs of onyx (from the Atlas Mountains) were famously used by Mies van der Rohe in Villa Tugendhat at Brno (completed 1930) to create a shimmering semi-translucent interior wall.{{cite web|title=The Interiors|url=http://www.tugendhat.eu|publisher=Villa Tugendhat|access-date=2 September 2017}}{{cite web|title=Tugendhat Villa in Brno|url=https://whc.unesco.org/en/list/1052|publisher=UNESCO|access-date=2 September 2017}}

The Hôtel de la Païva in Paris is noted for its yellow onyx décor, and the new Mariinsky Theatre Second Stage in St.Petersburg uses yellow onyx in the lobby.

The ancient Romans entered battle carrying amulets of sardonyx engraved with Mars, the god of war. This was believed to bestow courage in battle. In Renaissance Europe, wearing sardonyx was believed to bestow eloquence.Firefly Guide to Gems By Cally Oldershaw, p.168 A traditional Persian belief is that it helped with epilepsy.The Mining World, Volume 32, June 25, 1910, p.1267 Sardonyx was traditionally used by English midwives to ease childbirth by laying it between the breasts of the mother.Three thousand years of mental healing By George Barton Cutten, 1911 P.202

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{{Wiktionary|onyx}}

• {{cite EB1911|first=Frederick William |last=Rudler |wstitle=Onyx |volume=20 |page=118 |short=x}}

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Category:Chalcedony

Category:Quartz gemstones