Barite from the Linwood Mine, Buffalo, Iowa
Contributed by: Chris Clemens
minID: 2JR-L76
Date: Apr 26th, 2026
Locality: Linwood Mine, Buffalo, Scott County, Iowa, USA (See on Mindat)
Size: 9.2 x 5.9 x 13.8 cm
Weight: 517 g
Description:
Located adjacent to 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 crystals. Less known is that the Linwood Mine also produces the largest euhedral barite crystals in the United States. Some of the Linwood barites show a very interesting fluorescent/phosphorescent response under UV.
This is a specimen of light golden/smoky colored barite crystals on a siltstone matrix. The largest crystal measures 7.9 x 3.1 cm and is double terminated. These crystals are exceptionally transparent and well-formed. The barite shows a ghostly blue/white, fluorescent response with greenish phosphorescence under shortwave and midwave UV but is only dimly fluorescent under longwave.
Some of these photographs were featured in the article "Barite from the Linwood Mine", written by Jared Freiburg, et al., published in the Jan/Feb, 2017, issue of Rocks and Minerals.
Originally posted by Chris Clemens on Nature's Rainbows in 2017.
Summary of luminescence responses:
Baryte (Mindat) (RRUFF)
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: White
- Afterglow after exposure to Shortwave (254nm Lamp/Mercury) UV light: Blue
- Fluorescence under Midwave (305nm Lamp/Mercury) UV light: White
- Afterglow after exposure to Midwave (305nm Lamp/Mercury) UV light: Blue