Blue Spinel Gemstones
Spinel is a gemstone that at one time was most famous for being mistaken for ruby or sapphire. These days spinel gets the respect it deserves - it is recognized for its excellent hardness (8 on the Mohs scale), brilliance, and the fact that unlike most ruby and sapphire gemstones, spinel is never heated or treated in any way.
Spinel is now in great demand among gem dealers, who can rarely find enough stock to satisfy their customers. However, natural spinel is rarely found in the mainstream market, since the supply is so limited that most jewelry stores don't stock it.
Spinel is composed of magnesium aluminate and is typically colored by chromium and iron. It forms as a cubic crystal like a diamond. However, unlike diamond, which has perfect cleavage, spinel has very poor cleavage. That makes it both easier to cut and also a more durable gem for jewelry. Due to its very good dispersion, spinel gemstones can possess vivid fire. The intensity of spinel color is in part due to the fact that spinel is one of the few singly refractive gemstones, the others include garnet and diamond.
Red is the most famous color in spinel, but spinel occurs in a range of colors, including pink, violet, orange, silver and blue. The red and pink spinel are the most prized, followed by lavender and blue. Any spinel weighing over 2 carats is rare and good stones over 3 carats are considered to be very rare indeed.
Blue spinel is a rather special stone. There are few gems that occur naturally in blue. Blue sapphire is the most famous. Blue topaz is the result of irradiation treatment and tanzanite is often heated to enhance its blue color. In the deeper blue colors, there are only softer stones such as kyanite and iolite.
The colors of blue spinel range from blue-gray to violet-blue, greenish-blue and cobalt blue. The lighter tones tend to display more brilliance and fire. They also display the best attributes under different types of light. Some of the darker shades with a gray secondary hue can look less lively under incandescent lighting.
Burma and Sri Lanka are the traditional sources for fine spinel, though the Burmese material is generally recognized as superior. Recently some high quality African spinel has made an appearance, with some pieces in good sizes. We have found excellent spinel from Tanzania in red, pink, violet and blue; and occasionally in unusual colors such as orange and purple. The supply of Burmese spinel is very limited but steady, and the material is generally of very high quality.
- Erstausgabe: February-24-2009
- Zuletzt geändert: January-22-2019
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