California State Gemstone or Gem


Benitoite: California State Gemstone or Gem

BaTiSi3O9 - Barium Titanium Silicate

Adopted on October 1, 1985

Benitoite, (BaTiSi3O9 - Barium Titanium Silicate,) was designated as California official State Gemstone in 1985. Sometimes called the " blue diamond", it was first discovered near the headwaters of the San Benito River from which it derived its name. The gem is extremely rare and ranges in color from a light transparent blue to dark, vivid sapphire blue, and occasionally it is found in a violet shade.

Benitoite: California State Gemstone or Gem

Benitoite: California State Gemstone or Gem

Benitoite is a rare blue barium titanium silicate mineral, found in hydrothermally altered serpentinite. Benitoite fluoresces under short wave ultraviolet light, appearing bright blue to bluish white in color. The more rarely seen clear to white benitoite crystals fluoresce red under long-wave UV light.

It was first described in 1907 by George D. Louderback, who named it benitoite for its occurrence near the headwaters of the San Benito River in San Benito County, California.

Benitoite occurs in a number of sites, but gemstone quality material has only been found in California. In 1985 benitoite was named as the official state gem of California.

Benitiote has a rare 5 pointed crystal form, and an even rarer 6 pointed form, "star of David", with about 24 samples known

Benitoite is found with other rare minerals such as black-red neptunite, snow white natrolite and brown-yellow joaquinite. A rare cluster of blue Benitoite and black neptunite on top of a crust of white natrolite is a treat for mineral collectors.

Benitoite occurs in serpentine, California's state rock. The mineral Benitoite is the only natural occurrence of the ditrigonal-dipyramidal class, hexagonal system.

It is the only gem known in its crystal class. Its beautiful triangular crystals were predicted mathematically before any material in that class was ever found. The cut stones are brilliant blue, from colorless to deep blue and full of fire, since dispersion is only slightly less, equal to, or slightly higher than diamond. In recent years a few pink stones have been faceted. Hardness is satisfactory at 6.5, but it requires some care in setting and wearing it. Stone sizes are small, as only tips of crystals are gemmy. Gems much over one carat are uncommon and only about five a year are over two carats.

The sapphire-blue or colorless crystals are small; gem quality specimens larger than two carats are rare. Faceted stones are usually under 1 carat; the largest documented stone is 7.8 carats and resides at the Smithsonian. Benitoites sell for over $1000 per carat and the price has been raising rapidly as the deposit has been largely worked out and available gems sold.

One of the finest and rarest of gemstones, Benitoite combines the color of fine blue sapphire with the dispersion of diamond.

California Assembly Bill No. 2404 (FAILED)

Its rarity and occurrence in California moved the California Federation of Mineralogical Societies (CFMS) to propose that it be adopted as the state's official gemstone. Thus began a four-year effort that led to the introduction of legislation in the California State Legislature and the adoption of benitoite's adoption as California's official state gemstone.

California Assembly members Lucy Killea and Rusty Areias introduced Assembly Bill No. 2404 (AB 2404) on January 18, 1984. By the end of May, the bill had been adopted in the Assembly and read and referred to the Committee on Rules in the Senate. Unfortunately, AB 2404 was defeated in the Senate on June 29 by a vote of 17 to 10.

If at first you don't succeed, try, try again. And that's exactly what the California Federation of Mineralogical Societies did a year later.

California Assembly Bill No. 2357

On March 8, 1985, Assembly Bill No. 2357 (AB 2357) was introduced in the Assembly. Sponsored by Rusty Areias, this bill made it through the Assembly and the Senate and was signed into law, by Governor George Deukmejian, on October 1, 1985.


An act to add Section 425.3 to the Government Code , relating to the state gemstone.

[Approved by Governor October 1, 1985. Filed with Secretary of State October 1, 1985.]

The people of the State of California do enact as follows:

SECTION 1. Section 425.3 is added to the Government Code, to read:
425.3 Benitoite is the official state gemstone.

California Law

The law designating the Benitoite as the official California state gemstone is found in the California Government Code, Title 1, Division 2, Chapter 2, SECTION 420-429.8.

SECTION 420-429.8

425.3. Benitoite is the official state gemstone.


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