Along with a state mineral (gold) and state rock (serpentine)California has a state gemstone, benitoite. This rare gemstone is also known as the “blue diamond” because of its deep shades of transparent blue color. One of over 3,000 known minerals, benitoite is classified as a barium titanium cyclosilicate.
Benitoite was first discovered in 1907 in the San Benito Mountains. Two years later, it was given the label benitoite by a UC Berkeley mineralogist who named the gemstone after the place where it was discovered. Since then, it has been mined by the Benitoite Mining Company. The rare gemstone is only found in a few places throughout the world. The California Legislature designated benitoite as the official State Gemstone in 1985.
(Assembly Bill 2357, Chapter 1365, 1985)