Aragonite from Chihuahua, Mexico
Contributed by: Michael Crawford
Date: Jun 22nd, 2025
Locality: Chihuahua, Mexico (See on Mindat)
Size: 15 x 22 cm
Description:
A nice specimen of aragonite from Chihuahua, Mexico. The branching aragonite crystals form a beautiful Christmas tree pattern. This aragonite is a secondary mineral that formed in an open space such as a large vug or cave. The green fluorescence is brightest in shortwave UV illumination and the green fluorescence coverage is also greater in shortwave.
The shortwave emission spectrum shows that uranyl ions are the activator. There are fewer peaks and the peaks are shifted compared to a spectrum of meta-autunite.
Comparison of emission peaks
Aragonite Meta-autunite
503 nm 501 nm
523 nm 523 nm
544 nm 546 nm
560 nm 571 nm
600 nm
Summary of luminescence responses:
Aragonite
- Fluorescence under Longwave (365nm LED) UV light: Green
- Fluorescence under Midwave (305nm LED) UV light: Green
- Fluorescence under Shortwave (255nm LED) UV light: Green