Fluorescent Mineral Database

A new secret project! Trying to create a nice Fluorescent Mineral Database (FMDB), which would be searchable by mineral, locality, and luminescence properties. Also making it easy for people to contribute with their own specimens!

Dugway Geode, Dugway Geode Beds, Juab County, Utah

Contributed by: Chris Clemens
Date: Apr 25th, 2026
Locality: Dugway geode beds, Dugway Pass area, Juab County, Utah, USA (See on Mindat)
Size: 8.5 x 5.3 x 9.5 cm
Weight: 288 g

Description:
Many of the geodes collected from the famous Dugway Geode Beds in the Utah West Desert show impressive green fluorescence under UV. This example shows a classic Dugway geode consisting of a rhyolitic shell containing a hollow interior lined with chalcedony, quartz druse, and aragonite. Under shortwave UV the chalcedony shows green uranyl-activated fluorescence, and the aragonite shows a blue, white response with bright and lasting off-white phosphorescence. There is also another minor, unknown mineral present that shows small spots of sky-blue phosphorescence. These geodes are typically only weakly fluorescent, or not fluorescent, under longwave UV. This geode was collected in April of 2010.

Originally posted by Chris Clemens on Nature's Rainbows in 2016.

Fluorescence under shortwave UV light.
Fluorescence under shortwave UV light.
Afterglow after exposure to shortwave UV light.
Afterglow after exposure to shortwave UV light.
Normal light.
Normal light.
Normal light. Side 2.
Normal light. Side 2.
Normal light. Specimen size image.
Normal light. Specimen size image.

Summary of luminescence responses:

Chalcedony (Mindat) (RRUFF)

  • Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Green
Aragonite (Mindat) (RRUFF)
  • Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: White
  • Afterglow after exposure to Shortwave (254nm Lamp/Mercury) UV light: Yellow

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