Trona from Sweetwater County, Wyoming
Contributed by: Michael Crawford
Date: Oct 14th, 2025
Locality: Sweetwater County, Wyoming, USA (See on Mindat)
Size: 7 x 14 cm
Description:
A trona (Na3H(CO3)2 · 2H2O) specimen from Sweetwater County, Wyoming. Trona is an evaporite mineral that formed in an ancient lake bed. This specimen came from the Paleocene age Green River Formation.
The fluorescence is pale yellow under all wavelengths of UV illuminated. It is brightest under longwave light. The longwave emission spectrum is a very broad peak with a maximum at 476 nm. The trona fluorescence is likely activated by organics. Unlike some organic activated fluorescence, this specimen has no afterglow.
Summary of luminescence responses:
Trona (Mindat) (RRUFF)
- Fluorescence under Longwave (365nm LED) UV light: Yellow
- Fluorescence under Midwave (305nm LED) UV light: Yellow
- Fluorescence under Shortwave (255nm LED) UV light: Yellow