sapphire

sapphire
/saf"uyeur/, n.
1. any gem variety of corundum other than the ruby, esp. one of the blue varieties.
2. a gem of this kind.
3. the color of this gem, a deep blue.
adj.
4. resembling sapphire; deep blue: a sapphire sky.
[1225-75; < L sapphirus < Gk sáppheiros, prob. < Sem (cf. Heb sappir; ulterior orig. obscure); r. ME safir < OF < L, as above]

* * *

Transparent to translucent natural or synthetic variety of corundum that is highly prized as a gemstone.

Its colour is due mainly to the presence of small amounts of iron and titanium and normally ranges from very pale blue to deep indigo. Colourless, gray, yellow, pale pink, orange, green, violet, and brown varieties also are known as sapphire; red varieties are called ruby. Synthetic sapphire has been produced commercially since 1902. Much is used in jewelry, but most is used in the manufacture of jewel bearings, gauges, dies, and other specialized components; some also is used as a high-grade abrasive. It is found in Sri Lanka, Myanmar, India, and Montana in the U.S.

* * *

 transparent to translucent, natural or synthetic variety of corundum (q.v.; aluminum oxide, Al2O3) that has been highly prized as a gemstone since about 800 BC. Its colour is due mainly to the presence of small amounts of iron and titanium and normally ranges from a very pale blue to deep indigo, with the most valued a medium-deep cornflower blue. Colourless, gray, yellow, pale pink, orange, green, violet, and brown varieties of gem corundum also are known as sapphire; red varieties are called ruby. Much sapphire is unevenly coloured; it is also dichroic; that is, the colour of most varieties changes with the direction of view. Alexandrite sapphire appears blue in daylight and reddish or violet in artificial illumination, somewhat like true alexandrite. Careful heating and cooling under various conditions can induce permanent colour changes in sapphire (e.g., from yellow to colourless or greenish blue and from violet to pink). Other colour changes result from exposure to intense radiation. Most sapphire contains abundant microscopic inclusions; reflections from these yield a faint whitish sheen, known as silk. Tiny, regularly arranged mineral inclusions (commonly rutile) and elongate cavities are responsible for the asterism shown by star sapphire.

      Sapphire is a primary constituent of many igneous rocks, especially syenites, pegmatites, and various basic (silica-poor) types; it also occurs in schists and metamorphosed carbonate rocks. Most commercial production has come from alluvial gravels and other placer deposits, where the sapphire commonly is associated with ruby and other gem minerals. The best known sources, including some lode deposits, are in Sri Lanka, Myanmar (Burma), Thailand, Australia (Victoria, Queensland, New South Wales), India, Madagascar, Russia, South Africa, and the United States (Montana, North Carolina).

      Most transparent sapphire is faceted, generally in the brilliant style. Such gems have considerable sparkle, but they exhibit little fire because of their modest dispersion (separation of light into its component colours). Skillful cutting of unevenly coloured stones yields gems with a uniform appearance derived from only small portions of relatively deep colour. Star sapphire and other nontransparent varieties are cut en cabochon (in convex form, highly polished) rather than faceted. Despite its great hardness, some sapphire is carved or engraved, especially in the Orient.

      Synthetic sapphire has been produced commercially since 1902. Clear, sound material is manufactured in the form of carrot-shaped boules and slender rods. Much is consumed by the jewelry trade, but most synthetic material is used for the manufacture of jewel bearings, gauges, dies, phonograph-needle points, thread guides, and other specialized components; some also is used as a high-grade abrasive. Synthetic star sapphire is made with luminous stars that are more regular and distinct than those in most natural stones; the asterism is obtained through controlled exsolution of impurities.

* * *


Universalium. 2010.

Игры ⚽ Поможем написать реферат
Synonyms:

Look at other dictionaries:

  • Sapphire — Saltar a navegación, búsqueda Sapphire Organización Universidad de Stanford / Departamento de Defensa Satélite de Tierra Fecha de lanzamiento 30 de septiembre de 2001 …   Wikipedia Español

  • Sapphire — Sap phire (? or ?; 277), n. [OE. saphir, F. saphir, L. sapphirus, Gr. ?, of Oriental origin; cf. Heb. sapp[=i]r.] 1. (Min.) Native alumina or aluminium sesquioxide, {Al2O3}; corundum; esp., the blue transparent variety of corundum, highly prized… …   The Collaborative International Dictionary of English

  • Sapphire — steht für: Sapphire (Autorin) (* 1950), US amerikanische Autorin Sapphire Technology, Hardwarehersteller SAPphire (Messe), eine jährlich in USA und Europa staffindende Neuheitenmesse des Softwareunternehmens SAP ein Flugzeugtriebwerk, siehe… …   Deutsch Wikipedia

  • sapphire — late 13c., from O.Fr. saphir (12c.), from L. sapphirus (Cf. Sp. zafir, It. zaffiro), from Gk. sappheiros blue stone (the gem meant apparently was not the one that now has the name, but perhaps rather lapis lazuli, the modern sapphire perhaps… …   Etymology dictionary

  • Sapphire — Sap phire, a. Of or resembling sapphire; sapphirine; blue. The sapphire blaze. Gray. [1913 Webster] …   The Collaborative International Dictionary of English

  • Sapphire — Technology Отрасль микроэлектроника Продукция Графические карты, материнские платы Веб сайт www.sapphiretech.com Sapphire Technology тайв …   Википедия

  • sapphire — ► NOUN 1) a transparent blue precious stone which is a form of corundum. 2) a bright blue colour. ORIGIN Greek sappheiros, probably denoting lapis lazuli …   English terms dictionary

  • sapphire — [saf′īr] n. [ME < OFr saphir < L sapphirus < Gr sappheiros < Heb sapir < Sans śanipriya, lit., dear to Saturn < Śaniḥ, Saturn (the planet) + priya, beloved < IE * prī , var. of base * prēi , to love > FRIEND] 1. a clear,… …   English World dictionary

  • Sapphire — For other uses, see Sapphire (disambiguation). Sapphire The 423 carat (85 g) blue Logan sapphire General Category Oxide mineral …   Wikipedia

  • Sapphire — Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom. Sur les autres projets Wikimedia : « Sapphire », sur le Wiktionnaire (dictionnaire universel) Sapphire est Le terme anglais pour la pierre… …   Wikipédia en Français

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”