Benitoite
Contributed by: Michael Crawford
Date: Jun 10th, 2025
Locality: California State Gem Mine, Santa Rita Peak, San Benito County, California, USA (See on Mindat)
Size: 6 x 7 cm
Description:
A benitoite and neptunite specimen from the Benitoite Gem Mine, San Benito County, California. The pale blue benitoite crystals fluoresce red in longwave UV illumination. The darker blue crystals do not fluoresce in longwave light. All of the benitoite crystals fluoresce a bright blue in shortwave UV illumination.
According to fluomin.org, the red longwave fluorescence is activated by titanium (Ti3+) and either chromium (Cr3+) or manganese (Mn4+). The shortwave blue fluorescence is intrinsic and associated with isolated TiO6 octahedra.
Summary of luminescence responses:
Benitoite
- Fluorescence under Longwave (365nm LED) UV light: Red
- Fluorescence under Shortwave (255nm LED) UV light: Blue