Lava Cap Thunder Egg, Deming, New Mexico
Contributed by: Chris Clemens
Date: Apr 24th, 2026
Locality: Lava Cap Claim, Little Florida Mountains Mining District, Little Florida Mountains, Luna County, New Mexico, USA (See on Mindat)
Size: 42 x 20 x 47 mm
Description:
A cut, but unpolished, Lava Cap Thunder Egg half, containing chalcedony, calcite and manganese oxide pseudomorphs, enclosed in a rhyolite shell. There are also areas of aragonite coverage on the exterior of the rhyolitic shell. Under SW UV, the chalcedony fluoresces bright green and the calcite red. The aragonite shows a blue/white response with phosphorescence. These beautifully fluorescent thunder eggs occur on the Coleman Claim, Florida Mountains, Deming, New Mexico.
Originally posted by Chris Clemens on Nature's Rainbows in 2016.
Summary of luminescence responses:
Aragonite (Mindat) (RRUFF)
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: White
- Afterglow after exposure to Shortwave (254nm Lamp/Mercury) UV light: White
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Red
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Green