Calcite Crystals - Linwood Mine, Buffalo, Iowa

Contributed by: Chris Clemens
minID: WWQ-4G8
Date: May 21st, 2026
Locality: Linwood Mine, Buffalo, Scott County, Iowa, USA (See on Mindat)
Size: 14.6 x 7.2 x 15.1 cm
Weight: 1249 g

Description:
Located on the banks of the Mississippi River in Buffalo, Scott County, Iowa, the Linwood Mine is one of the largest underground limestone mines currently in operation in the United States. The Linwood Mine is known to produce beautiful, museum quality calcite and barite crystals. Of interest to fluorescent mineral collectors, the Linwood Mine also produces interesting fluorescent specimens.

This is a classic specimen from the Linwood Mine, consisting of colorless, transparent, modified rhombohedral calcite crystals, some with minor marcasite inclusions, on a minimal grey limestone matrix. This is a beautiful display specimen under normal light, but also shows a lovely, soft, purple/magenta, fluorescent response under midwave UV. As is the case with much of the fluorescent calcite from the Linwood Mine, this specimen shows its brightest response under midwave UV.

Originally posted by Chris Clemens on Nature's Rainbows in 2020.

Fluorescence under midwave UV light.

Normal light.

Summary of luminescence responses:

Calcite (Mindat) (RRUFF)

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