Terlingua Calcite- Terlingua, Texas
Contributed by: Chris Clemens
minID: F0F-6J2
Date: Apr 24th, 2026
Locality: Little 38 Mine, Brewster County, Texas, USA (See on Mindat)
Size: 6.4 x 5.4 x 13.3 cm
Weight: 333 g
Description:
Terlingua calcite is one of the most spectacular and beautiful fluorescent minerals due to its bright, multi-colored, multi-wave, fluorescent response, and bright, persistent phosphorescence. Terlingua calcite shows bright blue fluorescence under shortwave UV, with bright and long-lasting phosphorescence. Under longwave UV, the fluorescent response is bright pink. True Terlingua calcite comes from only one source- the mercury mines of Terlingua, Brewster County, Texas, with the most notable location being the Little 38 Mine, located 4 miles west of Terlingua. These mines have been closed for years, and many have been reclaimed, making the collection of new material very difficult, if not impossible. Calcite showing a similar fluorescent response, but collected from other locations, is referred to as "Terlingua-type" calcite.
Originally posted by Chris Clemens on Nature's Rainbows in 2016.
Summary of luminescence responses:
Calcite (Mindat) (RRUFF)
- Fluorescence under Longwave (365nm LED) UV light: Pink
- Fluorescence under Midwave (305nm Lamp/Mercury) UV light: Violet
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Blue