Benitoite crystals from San Benito County, California (actual crystal size is 1.5 cm); photo © John Veevaert / Trinity Mineral Company (used by permission).
Official State Gemstone of California
California designated benitoite as the official state gemstone in 1985. All State Gemstones
Benitoite is sometimes called the "blue diamond." First discovered near the headwaters of the San Benito River in 1907 (hence the name), benitoite is a very rare gem that ranges in color from a light transparent blue to dark, sapphire blue, or occasionally a violet shade.
Benitoite (pronounced "ben-ee-toe-ite") was initially thought to be a sapphire, but after careful analysis was found to be a mineral new to science. Gem quality benitoite crystals are found only in California.