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OFFICIAL GEMSTONE
While most gemstones are valued for color and clarity there are some valued for their rarity. The official state gem of California is extremely rare and comes from San Benito County.
In 1907, while looking for cinnabar, a mercury ore mineral, James Couch discovered benitoite. He was at the New Idria Mercury mine, near the San Benito River when he spotted the dark blue crystals among white silica. What he thought were sapphires turned out to be one of the top 12 rarest gems which today is worth $4000 per carat.
The Couch samples were sent to University of California Berkeley for analysis. Dr. George Louderback confirmed that the blue crystals were indeed a new mineral and named it after the area in which it was found.
According to John Veevaert, a geologist who currently owns the largest personal collection
of the blue mineral, “benitoite is unique in the world of crystals.” He explains that it provided mineralogists with more than just a new mineral. There are six basic Shapes of crystal formations – cubic, tetragonal, orthorhombic, hexagonal, triclinic and monoclinic. Early in the theoretical development of crystallography, it was hypothesized that there was a class of the hexagonal system that would produce trigonally (triangular) shaped crystals. The discovery of benitoite proved this hypothesis” The triangular shaped crystals are now referred to as Benitoite Type.
This multicolored gem is beautiful polished or in its natural state. The most common color is a deep sapphire blue with hints of violet but it can also be found in clear, white, pink and a green-gray color. Considered a double refracting crystal, benitoite radiates a
rainbow of colors when hit by light. The California Federation of Mineralogical Societies proposed that it be adopted as the state’s gemstone in 1984 and in 1985 it was made official.
Because it is only a 6.5 on the Mohs scale of mineral hardness (diamonds are a 10) it is not very strong. According to Veevaert this means benitoite is beautiful in pendants and bracelets but not a good choice for rings.
Benitoite is found in other parts of California and the country, but it does not match either the quantity or quality once found in San Benito County.
TOPS A Rock Shop in San Juan Bautista sells benitoite. Owner Kammie Osborn says: “The types of specimens that we have are rough pieces that have been worked. It’s a long process. You have to dip it in and out of acids to expose the rock.” The specimens found in the shop range from $4 to $1500, with faceted pieces. Actual gemstones that have been cut, range in price from $50 to $4000.
While the original mine in New Idria, now known as Benitoite Gem Mine, is no longer open day trips are available. It is open on the weekends via reservation for a fee of $70 per person with seniors and children being less.
