Fluorescent Mineral Database

A new secret project! Trying to create a nice Fluorescent Mineral Database (FMDB), which would be searchable by mineral, locality, and luminescence properties. Also making it easy for people to contribute with their own specimens!

Clinohedrite and Willemite - Franklin, New Jersey

Contributed by: Chris Clemens
Date: Apr 29th, 2026
Locality: Franklin Mine, Franklin, Sussex County, New Jersey, USA (See on Mindat)
Size: 64 x 31 x 74 mm
Weight: 246 g

Description:
This classic fluorescent rock from Franklin, New Jersey, contains orange, fluorescent clinohedrite, green fluorescing willemite, and black non-fluorescent franklinite. The clinohedrite and willemite fluoresce brightly under shortwave UV and show phosphorescence. A similar, but much dimmer response is seen under longwave UV.

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

Fluorescence under shortwave UV light.
Fluorescence under shortwave UV light.
Afterglow after exposure to shortwave UV light.
Afterglow after exposure to shortwave UV light.
Fluorescence under longwave UV light.
Fluorescence under longwave UV light.
Normal light.
Normal light.

Summary of luminescence responses:

Clinohedrite (Mindat) (RRUFF)

  • Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Orange
  • Afterglow after exposure to Shortwave (254nm Lamp/Mercury) UV light: Orange
Willemite (Mindat) (RRUFF)
  • Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Green
  • Fluorescence under Longwave (365nm LED) UV light: Green

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