Aragonite

Aragonite: Santa Eulalia District, Mun. de Aquiles Serdán, Chihuahua, Mexico.

The green fluorescence is caused by the uranyl ion [(UO₂)^2-], which cannot be incorporated by aragonite itself. During growth, thin crusts of hyalite-opal form on the aragonite. These microscopic layers can absorb the uranyl ion. So it is actually the embedded hyalite that fluoresces.

Aragonite with calcite (red) and sphalerite (Orange): Passa Limani Cove slag locality, Passa Limani area, Lavrion District, Attikí Prefecture, Greece.
Aragonite usually contains organic material, which causes a white to blue-green fluorescence. The red and orange fluorescence is due to calcite and sphalerite respectively.
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Aragonite on calcite: Yangshu, Guangxi Province, China. White fluorescing aragonite mainly due to organic matter, humic acids. The magenta fluorescence of the calcite is due to manganese and a little lead who both replace calcium.

Aragonite in clay: Pantoja, Toledo, Castile-La Mancha, Spain.
Fluorescence aragonite, greenish white, mainly by organic matter, humic acids.

Aragonite on calcite: Boverie quarry, Jemelle, Rochefort, Namur Province, Belgium
Fluorescence of aragonite, greenish white, mainly by organic matter, humic acids. Red fluorescent calcite, only in short-wave UV. The classic manganese and lead activator. The blue color is reflection of blue light of the UV lamp. This is a scan of a slide. It is also the first successful picture of a fluorescent mineral I ever made, meanwhile already some 25 years ago.

Aragonite and calcite: Boccheggiano mines, Montieri, Grosseto Province, Tuscany, Italy
This stuff is actually somewhat of a mix of calcite and aragonite. There are still persistent rumors that this would be a strontium aragonite. Wrong! Strontium has nothing to do with this impressive fluorescence. The activator is samarium. Check out the spectrum.

Aragonite with calcite (red) and cerussite (yellow): Passa Limani Cove slag locality, Passa Limani area, Lavrion District, Attikí Prefecture, Greece.
Aragonite is intergrown with cerussite, showing a more yellow tint than the normal greenish fluorescence..
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