Sapphire

sapphire, precious stone. A transparent blue corundum, it is classified among the most valuable of gems. Sapphires are found chiefly in Thailand, India, Sri Lanka, and Myanmar and also in Australia and in the United States (in Montana). The sapphires from Kashmir are of a beautiful cornflower blue and are highly valued. The Sri Lankan varieties are paler; those from Montana have a metallic luster; and the Australian sapphires are of a dark blue shade approaching black. The terms yellow sapphire, purple sapphire, and green sapphire are used alternatively with Oriental topaz, Oriental amethyst, and Oriental emerald for other varieties of corundum. Like rubies of similar structure, some sapphires display a six-pointed star when cut to a cabochon (round-topped) shape and exposed to direct sunlight. Such star sapphires are usually obtained from Sri Lanka. Synthetic sapphires are made by the fusion of aluminum oxide, with titanium oxide added as a coloring agent.

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sapphire

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.

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sapphire

1. 

a. any precious corundum gemstone that is not red, esp the highly valued transparent blue variety. A synthetic form is used in electronics and precision apparatus. Formula: Al₂O₃

b. (as modifier): a sapphire ring

2. the blue colour of sapphire

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sapphire [′sa‚fīr]

(mineralogy)

Any of the gem varieties of the mineral corundum, especially the blue variety, except those that have medium to dark tones of red that characterize ruby; hardness is 9 on Mohs scale, and specific gravity is near 4.00.

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sapphire

September. [Am. Gem Symbolism: Kunz, 319–320]

See : Birthstones

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sapphire

emblem of sexual purity. [Gem Symbolism: Kunz, 370]

See : Chastity

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Sapphire

a variety of the mineral corundum (A1₂0₃), characterized by its dark or light blue color, which is caused by the simultaneous presence of the impurities Ti and Fe. Sapphire is a precious stone of order I. Star sapphire is characterized by as-terism in the form of a six-rayed star, which is brought about by microinclusions of rutile.

Sapphire deposits are mainly placers and usually contain rubies. Sapphires are found in the Southern Urals in the USSR and in Thailand, Sri Lanka, and India.

Synthetic sapphires that are used in the jewelry industry are obtained in the same manner as corundum. White sapphire is a synthetic colorless corundum that contains less than 0.001 percent impurities and has many specific physical properties that make it very useful in microelectronics, quantum electronics, high-resolution optics, and audio-optics.

REFERENCE

Rubin i sapfir. Moscow, 1974.

A. S. MARFUNIN