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 short wave UV, with bright and long-lasting phosphorescence. Under long wave 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. The size of this specimen of Terlingua calcite is 13.3 x 6.4 x 5.4 cm, and it weighs 333 grams.
The photo montage above shows the beautiful multi-colored, multi-wavelength fluorescent response that Terlingua calcite is notable for.
Terlingua calcite shows bright blue fluorescence under short wave UV (left image above) and bright and lasting phosphorescence after the short wave source has been turned off (right image).
Under mid wave UV, lavender fluorescence is seen, followed by blue phosphorescence after the UV source has been turned off.
Perhaps the most beautiful fluorescence shown by Terlingua calcite is the bright pink response seen under long wave UV. Although phosphorescence does occur following exposure to long wave UV, it is brief and dim relative to that seen following short and mid wave UV.