Calibrated Black Star Sapphire
Specify size, shape and quality when ordering. Prices are subject to change without notice. Actual carat weight may vary from the average carat weight listed.
Black star sapphires differ from other corundum in that their color is not due to trace elements or color centers. Instead, it is caused by the color of exsolved hematite-ilmenite silk inclusions.
Black Star Sapphire - A cabochon cut black sapphire with a 6 ray star. These stones are always heat treated to improve their color.
Black star sapphires are not nearly as expensive and rare as other colors. Fine larger black star sapphires can cost a few hundred dollars per carat if they are of exceptional quality.
Summer 1937, New black star sapphires found, p. 98, 1p.
Fall 1939, Lined, foil-backed corundum produces stars and cat's-eyes, p. 36, 1p.
Winter 1944, American synthetics available from Linde, p. 185, 1p.
Also referred to as Bio Lemon Black Star Sapphire:A black sapphire formed from corundum with Titanium and Iron impurities.
The most common star sapphire is a black star sapphire; these are opaque in body color and can exhibit a well defined star; Most of these are small and are low in price. Larger black stars, if fine in quality may be moderately priced.
Black Star Diopsides are occasionally confused with Black Star Sapphires which exhibit six or twelve rays. Chrome Diopside is the variety most often seen faceted, whereas Violane is generally used for beads and inlay work.
Commercial grade stones (whitish or grayish blue, poorer star) of similar weight sold for $50-300/ct.
Black star sapphire of even the finest quality generally sell for under $50/ct (wholesale), ...
Diopside is found in two forms, the black star diopside, and the green emerald-like Chrome diopside.Diopside also offers a classic four rayed star stone that is very much like a black star sapphire ...
Sources -- Blackish green four-ray star enstatite cabochons from India and Sri Lanka are plentiful and inexpensive. They are often used as cheap (and much softer) substitutes for black star sapphires.
depends on the sharpness of star, symmetry of the rays, and the body color. The American Museum of Natural History in New York City houses the largest cut star sapphire, the 543-carat "Star of India", and the "Midnight Star", a black star sapphire.
Parallel needle-like inclusions are responsible for the effect. Examples include star diopside (4 rays) and star ruby (6 rays). Double asterism (12 rays) can be seen in small percentage of black star sapphires.
The Kazanjian Brothers gem and jewelry company had recently completed a fabulous Lincoln head carving of black star sapphire and were presently searching the world market for some big chunks of ruby, ...
 See also: Sapphire, Star Sapphire, Star, Stone, Color
  
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