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The Gemstone Kyanite

Round Cut Kyanite from Nepal

Kyanite is more of a collector gem then a mainstream gem, and has not been extensively mined for gem use. Gem quality Kyanite has traditionally come from Brazil, Cambodia, and Burma, but these stones are generally not colored consistently . They usually have a grayish tone, and are not fully transparent, thus limiting their use as a gemstones. However, recent finds in Nepal of high quality Kyanite have been delivering gemstones of exceptional blue color and transparency, rivaling Sapphire.

Color

? Blue

Hardness

? 4.5 - 7

Chemical Formula

? Al2SiO5

Mineral Class

? Kyanite

Additional Properties

Crystal System
? Triclinic
Refractive Index
? 1.71 - 1.73
Double Refraction
? -0.015
Transparency
? Transparent to translucent
SG
? 3.5 - 3.7
Luster
? Vitreous
Cleavage ? 1,1;2,1

All About

The blue color of Kyanite is usually inconsistent in crystals, with lighter and darker color zones and streaks often present. This can make cutting a crystal into a gem a challenge as color consistency in a gem is more desirable. Kyanite can also form in other colors such as colorless, white, green, yellow, and orange, but these other colors are uncommon, and generally only the blue color is used as a gemstone. Kyanite gemstones rarely display asterism in cabochons.

Kyanite is the most anisotropic of all gemstones, meaning its hardness differs on its horizontal and vertical sides. It is fairly soft when cut parallel to the long axis of the crystal, with a hardness of only 4.5 to 5.5. On the shorter side of the crystal the hardness is 6 to 7. This unique hardness property plays a role when cutting a crystal. Care must also be exercised not to scratch Kyanite gems as they are fairly soft for a gemstone (specifically on their horizontal axis).

Uses

? Kyanite is used as a minor blue gemstone. It is can be cut into various gemstone facets and cabochons. In jewelry, its use is limited mostly to earrings and pendants.

Other Names

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Treatments & Enhancements

? Kyanite gemstones are not heated or enhanced.

Kyanite Sources

? Traditional Kyanite sources of gem crystals include Brazil, Cambodia, Burma (Myanmar), Switzerland, Russia, Kenya, and the U.S. (North Carolina, Connecticut, and Maine). A relatively recent discovery of Kyanite in Nepal in 1995 has produced gem crystals of Kyanite of exceptional color and transparency.

Similar Gemstones

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Sapphire can appear similar to Kyanite, but can be distinguished by its greater hardness. Iolite is visibly pleochroic, and Tanzanite is usually lighter in color and has a more purplish hue.

Kyanite Photos

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Kyanite in the Rough Photos

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