Calcite Crystals and Fluorite, with Multi-Wave Response - Illinois Fluorospar District
Contributed by: Mark Cole
Date: Apr 7th, 2026
Locality: Illinois-Kentucky Fluorspar District, USA (See on Mindat)
Size: 3.5 x 2 x 4 inches
Weight: 17.5 oz
Description:
Last year (2017) the midwest chapter of the FMS had their annual meetup in Marion Kentucky, followed by an evening of collecting at the Minerva Mine in Southern. Illinois. I showed off some Greenland rocks, lights, and stuff and later the entire group went on a tour of the wonderful museum. Since I had already been on the tour twice before I hung back and explored the gift shop with my UV light. Came across this beauty and picked it up since it fluoresced so nicely under SW. I had no idea what lay in wait under MW and LW! An exceptional specimen - very happy with this find.
Originally posted by Mark Cole on Nature's Rainbows in 2018.
Summary of luminescence responses:
Calcite (Mindat) (RRUFF)
- Fluorescence under Longwave (365nm LED) UV light: Orange
- Fluorescence under Midwave (305nm Lamp/Mercury) UV light: Violet
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Orange