Gypsum fluorescence in visible and UV light

Geology has long studied the phenomenon of mineral fluorescence, that is, their ability to glow in different colors in ultraviolet radiation. More than 3,000 minerals have been discovered in nature, of which about 500 are fluorescent. This means that almost any rock can contain fluorescent inclusions. The most famous fluorescent minerals are fluorite, carbonate minerals (calcite, dolomite, magnesite, aragonite and others), apatite, zircon, and scheelite. A wide variety of minerals can fluoresce. Among them are precious stones-diamond, ruby, sapphire, topaz, spinel, kunzite, opal, lapis lazuli, turquoise, amber, but there are also "simple" minerals that also have this ability. Gypsum is one of the most common fluorescent minerals. In long-wavelength UV light, gypsum glows in yellow, orange, blue, or green tones.

A less well — studied area is the luminescence of gypsum and other minerals under the influence of light in the visible part of the spectrum. In 2014, American scientists Charles Mazel and Earl Verbeek investigated the extensive collection of the Franklin Mineral Museum in New Jersey. The phenomenon of mineral fluorescence under blue light in the visible spectrum was studied in detail, and a comparison was made with the effect of daylight, as well as short-and long-wave UV spectra.

A full-fledged study was published in September 2014 in the journal of the Franklin-Ogdensburg Mineralogical Society and is not publicly available: in this news you can only see photos of gypsum stone (sample 10 x 6.5 x 3 cm), luminescent under the described conditions.:

1. Daylight: white-gypsum, black inclusions-franklinite (does not fluoresce).

2. Blue light: yellow-green fluorescence-gypsum, green stripe on the left-top-interspersed with willemite.
3. Short-wave UV light: weak white-blue glow — gypsum, bright green-willemite.

4. Long-wave UV light: a faint white glow — gypsum, there is also a barely noticeable greenish glow of willemite.