Calcite and Fluorite from the Moscona Mine, Spain
Contributed by: Michael Crawford
Date: Aug 7th, 2025
Locality: Moscona Mine, El Pontón de Solís, Corvera de Asturias, Asturias, Spain (See on Mindat)
Size: 5 x 7 cm
Description:
A specimen of calcite scalenohedral crystals on a cluster of brown fluorite cubes from the Moscona Mine, El Ponton de Solis, Corvera de Asturias, Asturias, Spain. The calcite fluoresces bright pinkish red under midwave illumination. It is dimmer under longwave and shortwave UV light. The fluorite fluoresces pale violet and pale yellow under longwave UV light. Zoning in the fluorite crystals is most obvious under longwave light. Some cores of the fluorite cubes have pale violet fluorescence and pale-yellow outer zone. The colors are switched in other cubes. The fluorite fluoresces pale yellow under midwave light and white under shortwave light.
The fluorite has long lasting afterglow from exposure to all UV wavelengths. Longwave afterglow is green, and the afterglow becomes bluish white after exposure to shortwave light.
The longwave emission spectrum is a mixture of europium activated fluorescence with a peak at 422 nm and organic activators that give the fluorescence a whitish and yellowish hue. Organics also cause the green afterglow. The europium activated fluorescence is diminished under midwave and shortwave light and the fluorite fluorescence is dominated by organic activation.
The calcite red fluorescence is activated by manganese replacing calcium. The shortwave spectrum shows strong ultraviolet fluorescence activated by cerium. Cerium is the likely cause of the steep rise in violet emission under midwave illumination. The combination of this violet emission and the red emission caused by manganese gives the calcite the bright pinkish red color.
Summary of luminescence responses:
Fluorite (Mindat) (RRUFF)
- Fluorescence under Longwave (365nm LED) UV light: Purple
- Fluorescence under Midwave (305nm LED) UV light: White
- Fluorescence under Shortwave (255nm LED) UV light: White
- Afterglow after exposure to Longwave (365nm LED) UV light: Green
- Afterglow after exposure to Midwave (305nm LED) UV light: White
- Afterglow after exposure to Shortwave (255nm LED) UV light: White
- Fluorescence under Midwave (305nm LED) UV light: Pink
- Fluorescence under Shortwave (255nm LED) UV light: Red