Calcite, Valders Quarry, Manitowoc, Wisconsin
Contributed by: Chris Clemens
minID: 4XP-W1U
Date: Apr 20th, 2026
Locality: Valders Quarry, Manitowoc County, Wisconsin, USA (See on Mindat)
Size: 54 x 51 x 89
Weight: 237 g
Description:
This piece consists of a plate of milky white, translucent, scalenohedral calcite crystals and minor marcasite on a flat matrix of light grey limestone/dolostone. The calcite crystals show an unusual purple/blue, fluorescent response under midwave UV (305 nm). Interestingly, the calcite is not significantly fluorescent under shortwave or longwave UV. This specimen is from an uncommon midwestern location, the Valders Quarry, in Valders, Manitowoc County, Wisconsin.
The Valders Quarry is an open pit dolomitic limestone quarry, which produces harbor rock, gravel, and a very hard and weather resistant type of marble. It is located in the town of Valders, east of Manitowoc, in east central Wisconsin.
Originally posted by Chris Clemens on Nature's Rainbows in 2019.
Summary of luminescence responses:
Calcite (Mindat) (RRUFF)
- Fluorescence under Midwave (305nm Lamp/Mercury) UV light: Violet