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The Gemstone Benitoite

Benitoite is a rare gemstone, and for all practical purposes only comes from a single limited deposit in California. It is a relatively new gemstone, and was first discovered in 1907. Benitoite gemstones have a sapphire-blue color, and can have very good transparency and luster. Due to its rarity and lack of availability, Benitoite can be extremely expensive per carat.

Color

Blue

Hardness

6 - 6.5

Chemical Formula

BaTiSi₃O₉

Mineral Class

Benitoite

Additional Properties

Crystal System
Hexagonal

Refractive Index
1.75 - 1.80

Double Refraction
0.047

Transparency
Transparent

SG
3.6

Luster
Vitreous

Cleavage 3,1

All About

Although Benitoite is a valuable and exquisite gemstone, its hardness as a gemstone is relatively low and it is therefore prone to scratching. Large crystals of Benitoite are very rare, and they are usually preserved as mineral specimens. Therefore, gemstones of Benitoite are almost always very small, rarely exceeding two carats. Benitoite gemstones are strongly fluorescent, and give off a bright light blue color in shortwave ultraviolet light.

Uses

Benitoite is not a typical gemstone, and is mostly reserved for collectors and connoisseurs of exquisite gemstone. It is most often cut in round or oval cuts, though it is not usually seen in jewelry items.

Treatments & Enhancements

Benitoite gemstones are natural and not enhanced.

Benitoite Sources

Though there are several small-scale deposits of Benitoite worldwide, the only deposit capable of producing gemstone material is the Diablo Range, near the headwaters of the San Benito River, in the Southern tip of San Benito Co., California. This deposit is no longer actively producing Benitoite, thereby adding to the scarcity of this gemstone.

Similar Gemstones

Although Benitoite can resemble other gemstone such as Sapphire, Iolite, and Tanzanite, its origin is usually enough to identify it without it getting confused with other gemstones.