Color Change Calcite - Franklin, New Jersey

Contributed by: Chris Clemens
Date: Apr 29th, 2026
Locality: Buckwheat dump mineral collecting site, Franklin Mine, Franklin, Sussex County, New Jersey, USA (See on Mindat)
Size: 6 x 6 x 8 cm
Weight: 234 g

Description:
This is an interesting calcite specimen that was collected during the 2017 Super Digg at Franklin, New Jersey. Found at night on the Buckwheat Dump, this calcite shows a unique multi-wavelength fluorescent response under UV. Under shortwave UV the calcite fluoresces bright red/pink but shows a deep blue response under longwave UV.

Originally posted by Chris Clemens on Nature's Rainbows in 2017.

Fluorescence under shortwave UV light.

Fluorescence under longwave UV light.

Normal light.

Summary of luminescence responses:

Calcite (Mindat) (RRUFF)

• Fluorescence under Longwave (365nm LED) UV light: Blue
• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Red