In 1907 Benitoite was discovered by prospector Jim Couch, while he was searching for quicksilver. Jim Couch was grubstaked by R.W. Dallas. Couch received little for his part as the original discoverer. Active mining was pursued at the Gem Mine from 1907 to 1912 where a tunnel was dug following the vain. It was believed to be sapphire at first, but was soon identified as an unknown crystal, found nowhere else in the world. From 1912 to 1920, the mine was dormant, probley because of World War I. B.Suit, of San Benito Gem Co., leased the property but little work progressed until 1933, when the mine was reopened by M.Dunn who removed a quantity of material. In the 50's, M.F.Hotchkiss leased and bulldozed the old dumps looking for large blocks of veined blue schist to treat with acid. Around 1952, C.L.Cole, took over the lease and reopened the pit, he had a little shop in Oakland where you could see large plates of Benitoite crystals displayed in the store front window. Some of the most spectacular pieces sold from around three hundred dollars at that time.

In 1967, Gray and Forrest took over the lease and later purchased the property. Forrest and Gray had a successful career of working the mine.

Kennecott evaluated the site in the mid 1990's and did not opted for a lease.

In 2000, Brian Lees purchased the mine from Gray and Forrest and worked the mine for five winters.

In 2005, David Schreiner bought the mine and has opened it to the public. Now you can go and find free-floating Benitoite crystals, and some small plates.