A Midwestern Beauty: Multi-Wave Calcite Crystals - Sweetwater Mine, Reynolds County, Missouri

Contributed by: Chris Clemens
minID: UPT-PTD
Date: May 19th, 2026
Locality: Sweetwater Mine, Ellington, Reynolds County, Missouri, USA (See on Mindat)
Size: 40.8 x 35.8 x 54.1 mm
Weight: 52 g

Description:
This is a cluster of milky white calcite crystals from the Sweetwater Mine, Ellington, Viburnum Trend District, Reynolds County, Missouri, that shows a spectacular multi-colored fluorescent response under all UV wavelengths. Under shortwave UV (254nm) the calcite fluoresces red, but shows a bright saturated orange response under midwave UV (302nm), and a pink/magenta response under longwave UV (365nm).

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.

Summary of luminescence responses:

Calcite (Mindat) (RRUFF)

• Fluorescence under Longwave (365nm LED) UV light: Violet
• Fluorescence under Midwave (305nm Lamp/Mercury) UV light: Orange
• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Orange