Calcite, Fluorite and Sphalerite- Rosiclare, Illinois

Contributed by: Chris Clemens
minID: 28U-MU0
Date: May 18th, 2026
Locality: Rosiclare, Hardin County, Illinois, USA (See on Mindat)
Size: 45.4 x 38.6 x 74.9 mm
Weight: 176 g

Description:
This is a mixed specimen containing calcite, fluorite, sphalerite and likely other minerals. It was self-collected in 2015 at the tailings pile, Rosiclare Lead and Fluorspar Mining Co., Rosiclare, Illinois. This piece shows a similar fluorescent response under SW, MW and LW UV- the fluorite is yellow, calcite pink/orange and blue/white, and sphalerite mustard yellow/orange. There is also an unknown mineral that shows a blue phosphorescent response following exposure to SW UV.

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

Fluorescence under shortwave UV light.

Fluorescence under midwave UV light.

Fluorescence under longwave UV light.

Normal light.

Afterglow after exposure to shortwave UV light.

Summary of luminescence responses:

Calcite (Mindat) (RRUFF)

• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Pink
• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: White

• Fluorescence under Longwave (365nm LED) UV light: Blue