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Benitoite Facts

Benitoite Facts
Benitoite is a relatively new California gem mineral discovered 1907 and was thought to be sapphire. The location of the mine where the deposit exists is in the southeastern part of San Benito County, California, near the Fresno County line. The chemical classification of benitoite is barium titanium silicate. There are some colorless specimens but most are ligh blue to deep indig blue, and als bluish-gray and purplish-blue. Rare orange heat-treated specimens are also known. Benitoite's streakmay be white but is usually colorless, luster is vitreous, and its cleavage is poor. On the Mohs Hardness scale, it scores between a 6 to 6.5 with a specific gravity of 3.6. It has a crystal system that is hexagonal and its uses include gemstones and collector minerals.
Interesting Benitoite Facts:
The deposit occurs in a large area of serpentine which extends for many miles. The serpentine presents different phases from hard dark-green and greenish-black material to softer lighter-colored rock.
The crystal structure of the mineral is very unique and a one-of-a-kind mineral in its class, mostly due to its rare hexagonal crystallization.
Most of the crystals are first embedded in thick natrolite, and specimens are prepared for collectors by dissolving the natrolite in acid to expose the rare crystal.
The name benitoite name comes from its locality in San Benito County, California. The area is the only location in the world where the mineral can be found except for a few very sporadic and extremely limited occurrences elsewhere.
Benitoite is insoluble in ordinary acids, but is attacked by hydrofluoric acid and dissolves in fused sodium carbonate.
In shortwave ultraviolet light benitoite will appear as strongly fluorescent light blue. Some crystals form a dull red in longwave.
Benitoite is classified as a metamorphic rock.
Due to its rarity and lack of availability, per carat, benitoite can be quite expensive, and rarely exceeds two carats in size.
The largest perfect stone cut so far weighs over 7 carats and is about three times as heavy as the next largest flawless gem so far obtained.
Overall, its relative hardness for a gemstone is low and often is prone to scratching.
Though it is a gemstone, it is not used that often in jewelry items. It is most often cut in round or oval cuts, and mostly reserved for collectors.
The original area where benitoite was found is no longer an active mine, which is adding to its scarcity and value.
Sometimes benitoite can resemble other gemstones such as sapphire, iolite, and tanzanite, though it is usually easy to identify and does not get confused with the others.
Beniotite is the official gemstone of California.


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