Source: San Benito County, California, USA (only known
Chemical: BaTiSi3O9 (barium titanium silicate)
Formation: Forms in a veins of natrolite in a
Crystal System: Hexagonal
Unusual Properties: Seldom seen as a gemstone due to
extreme rarity and overall small sizes of cutable material. Estimates
from one source tells me that only about 5,000 carats of cutable
benitoite has been taken from the ground. The photo above is a
1.11 carat specimen in Your Gemologist's collection. The unusual
property of this stone is that it will fluoresce bright blue to
short wave ultraviolet light as seen below.
Colors: Colorless, blue and rarely pink
Wearability: With a hardness of 6-6.5 it would be
comparable to a tanzanite for wear and tear in jewelry.
RI: 1.757 - 1.804
Optical Character: U+
Hardness: 6 - 6.5
Shown above is a rock from a mine run of benitoite
ore. Photo#1 is the rock showing the light blue benitoite crystals
in matrix with the neptunite crystals (black) the natrolite skin
mineral (white) and the native host rock. Photo #2 is a close
up of the benitoite (blue) crystals. Photo #3 is this same area
under short wave ultraviolet light. All photos by Robert James FGA, GG.