Fluorescent, Phosphorescent, Triboluminescent Sphalerite - Frisco, Utah

Contributed by: Chris Clemens
minID: JP8-TGV
Date: Apr 27th, 2026
Locality: Frisco, San Francisco Mining District, Beaver County, Utah, USA (See on Mindat)
Size: 8 x 2.4 x 8.7 cm
Weight: 219 g

Description:
This is an outstanding specimen of sphalerite that displays several very interesting luminescent phenomena. It was collected from an unknown mine in the area of the San Francisco Mountains, Frisco, Beaver County, Utah. Under all wavelengths of UV light, this specimen shows a bright orange, fluorescent response with orange phosphorescence, brightest under long wave. Most interesting about this piece is its triboluminescence. Triboluminescence is the property of some minerals by which they emit flashes of light as their surface is scratched or rubbed by a hard object. In the case of this sphalerite specimen, the triboluminescence is orange and can be induced by scratching the surface with any hard object, including a fingernail. In the photograph shown here, the point of a metal nail was used. This piece is a cut end slab, with a sawn flat surface on one side- perfect for demonstrating its triboluminescent property.

Originally posted by Chris Clemens on Nature's Rainbows in 2017.