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!

Fluorite - Illinois-Kentucky Fluorspar District, Cave-In-Rock, Illinois

Contributed by: Chris Clemens
Date: Apr 28th, 2026
Locality: Cave-in-Rock Mining Sub-District, Hardin County, Illinois, USA (See on Mindat)
Size: 61 x 56 x 67 mm
Weight: 182 g

Description:
Cluster of large, light purple, stepped, fluorite cubes, from the historic Illinois-Kentucky Fluorspar District, Cave-In-Rock, Hardin County, Illinois. The fluorite contains numerous small hydrocarbon inclusions which are fluorescent under UV. Under shortwave the fluorite fluoresces light blue and the hydrocarbon inclusions white. The fluorite responds with deeper purple/blue fluorescence under longwave, again with the hydrocarbon inclusions showing a white response.

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:

Fluorite (Mindat) (RRUFF)

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

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