Calcite Crystals - Linwood Mine, Buffalo, Iowa

Contributed by: Chris Clemens
minID: 64U-V9E
Date: May 20th, 2026
Locality: Linwood Mine, Buffalo, Scott County, Iowa, USA (See on Mindat)
Size: 16.4 x 9.6 x 18.5 cm
Weight: 2.31 kg

Description:
This is a large cluster of transparent, modified rhombohedral calcite crystals on limestone matrix. It was collected in 2016 from the Linwood Mine, Scott County, Buffalo, Iowa. At its best under midwave UV, this piece shows a moderate pink/purple response. Under shortwave UV the calcite fluoresces a dimmer red/pink color. A dim red-orange response is seen under longwave UV.

Located adjacent to the Mississippi River, the Linwood Mine is one of the largest underground limestone mines currently in operation in the United States.

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