Calcite Crystals with Organic Inclusions - Linwood Mine, Buffalo, Scott County, Iowa

Contributed by: Chris Clemens
Date: Apr 27th, 2026
Locality: Linwood Mine, Buffalo, Scott County, Iowa, USA (See on Mindat)

Description:
Calcite, modified scalenohedrons with dark marcasite inclusions. Linwood Mine, Buffalo, Scott County, Iowa, USA. Under longwave UV (365nm) probable organic inclusions, visible as tan regions near the base of the crystals under visible light, fluoresce white. Under shortwave UV (254nm) the organic inclusions again show a white response, accompanied by pastel pink fluorescence more evenly distributed though the crystals, possibly due to manganese/lead activation.

Originally posted by Chris Clemens on Nature's Rainbows in 2017.

Fluorescence under longwave UV light. FOV = 4.9 cm x 3.3 cm

Fluorescence under shortwave UV light. FOV = 4.9 cm x 3.3 cm

Normal light. FOV = 4.9 cm x 3.3 cm

Summary of luminescence responses:

Calcite (Mindat) (RRUFF)

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