Fluorescent and Phosphorescent Calcite with Fluorescent Quartz from East Gray's Quarry, Glendo, Platte County, Wyoming
Contributed by: FMS Admin
Date: Feb 27th, 2026
Locality: Platte County, Wyoming, USA (See on Mindat)
Size: 3 x 1.25 x 4.5 inches
Weight: 12 oz
Description:
Calcite from this locale is known for fluorescing different colors when exposed to different wavelengths of ultraviolet light. This one has a vug lined with calcite. Within the calcite are druzy crystals of quartz that fluoresce green. Calcite fluoresces white. There is a blue, white calcite phosphorescence when the SW and MW lamps are removed.
Shortwave picture was taken at ISO-100, f/11 for 2 seconds.
Originally posted by John Rofrano on Nature's Rainbows.
Summary of luminescence responses:
Calcite (Mindat) (RRUFF)
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Yellow
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Green