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!

Metauranocircite - Davier Mine, South Dakota

Contributed by: Chris Clemens
minID: N6D-X1V
Date: Apr 27th, 2026
Locality: Davier Mine, Annie Creek, Bald Mountain Mining District (Portland Mining District), Lawrence County, South Dakota, USA (See on Mindat)
Size: 19.1 x 4 x 39.7 mm
Weight: 4 g

Description:
Small yellow/green, plate-like, crystals of metauranocircite on a dark limonitic stained Rhyolite matrix. From the Davier Mine, located in the northern Black Hills, Lawrence County, South Dakota. Metauranocircite is a secondary uranium mineral that typically forms in the oxidized zone of some uranium deposits. As is the case with most secondary uranium minerals, the metauranocircite fluoresces bright green under UV. This specimen is radioactive, emitting approximately 400 cpm at 1 cm.

Originally posted by Chris Clemens on Nature's Rainbows in 2017.

Fluorescence under shortwave UV light.
Fluorescence under shortwave UV light.
Fluorescence under longwave UV light.
Fluorescence under longwave UV light.
Normal light.
Normal light.

Summary of luminescence responses:

Metauranocircite (Mindat) (RRUFF)

  • Fluorescence under Longwave (365nm LED) UV light: Green
  • Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Green

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