Crazy Calcite - Franklin, New Jersey

Contributed by: Chris Clemens
minID: JQ2-LLD
Date: Apr 25th, 2026
Locality: Franklin Mine, Franklin, Sussex County, New Jersey, USA (See on Mindat)
Size: 56.6 x 32.3 x 67 mm
Weight: 134 g

Description:
Crazy calcite is an unofficial local name applied to a type of rock containing dolomite in calcite from Franklin, New Jersey, that fluoresces two shades and intensities of red under shortwave UV (254nm). The calcite fluoresces bright orange/red, and the dolomite shows a maroon, red response. This specimen is also reactive under midwave UV (305nm), with the calcite fluorescing a deeper, more cherry red color, and the dolomite showing a dimmer red/purple response.

Originally posted by Chris Clemens on Nature's Rainbows in 2016.

Fluorescence under midwave UV light.

Fluorescence under shortwave UV light.

Normal light.

Summary of luminescence responses:

Calcite (Mindat) (RRUFF)

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

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