Barite, Skunk Pocket, Linwood Mine, Buffalo, Iowa

Contributed by: Chris Clemens
minID: M8X-Q4Y
Date: Apr 16th, 2026
Locality: Linwood Mine, Buffalo, Scott County, Iowa, USA (See on Mindat)
Size: 14.5 x 10.2 x 17.4 cm
Weight: 2.43 kg

Description:
This large and aesthetic barite specimen was collected from the Linwood Mine, Buffalo, Scott Co., Iowa from a find made in November 2019 called the "Skunk Pocket". The Skunk Pocket is notable for the brightness and unique pattern of fluorescence of the barite specimens it produced. Consisting of yellow-amber colored prismatic crystals, the barite specimens from the Skunk Pocket are distinct in that some of the crystal faces have a thin secondary barite deposit on their surface, giving them a frosted appearance. Under all UV wavelengths, these frosted surfaces show a preferential bright blue-white, fluorescent response, with strong and lasting phosphorescence. The central face of each prism has no secondary barite coating, and is therefore not fluorescent, producing a striped pattern under UV that is reminiscent of a striped skunk, thus providing the suggestion for the name of the "Skunk Pocket".

This skunk barite specimen shows bright blue-white fluorescence under longwave UV (365 nm). Note the preferentially fluorescent crystal faces with the central non-fluorescent surface, giving rise to the name of the "Skunk Pocket". After the longwave UV source is turned off, bright and lasting green phosphorescence is seen. Similar blue-white fluorescence is also seen under shortwave UV (254 nm), but not as bright as the longwave UV response. Following exposure to shortwave UV (254 nm), pale blue-green phosphorescence is seen.

Located adjacent to the Mississippi River in Scott County, Iowa, 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 2023.

Fluorescence under longwave UV light.

Afterglow after exposure to longwave UV light.

Fluorescence under shortwave UV light.

Afterglow after exposure to shortwave UV light.

Normal light. Note the frosted crystal faces resulting from secondary barite deposition.

Summary of luminescence responses:

Baryte (Mindat) (RRUFF)

• Fluorescence under Longwave (365nm LED) UV light: White
• Afterglow after exposure to Longwave (365nm LED) UV light: Green
• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: White
• Afterglow after exposure to Shortwave (254nm Lamp/Mercury) UV light: Blue