A Midwestern Midwave UV Mineral Treasure - Sweetwater Mine, Reynolds County, Missouri

Contributed by: Chris Clemens
minID: MEA-HDF
Date: May 22nd, 2026
Locality: Sweetwater Mine, Ellington, Reynolds County, Missouri, USA (See on Mindat)
Size: 12.9 x 10.8 x 16.6 cm
Weight: 1110 g

Description:
This is a true Midwestern midwave UV fluorescent mineral treasure from the Sweetwater Mine, Ellington, Reynolds County, Missouri. Featuring numerous, brightly fluorescent, modified calcite scalenohedrons on a limestone matrix with calcite druse and brassy chalcopyrite crystals (non-fluorescent). As shown below, the large calcite crystals fluoresce a bright pastel pink color under midwave UV (302 nm) and the calcite druse shows a contrasting moderate off-white response. Interestingly, this specimen is not significantly fluorescent under shortwave or longwave UV.

Originally posted by Chris Clemens on Nature's Rainbows in 2022.

Fluorescence under midwave UV light.

Normal light.

Summary of luminescence responses:

Calcite (Mindat) (RRUFF)

• Fluorescence under Midwave (305nm Lamp/Mercury) UV light: Violet