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!

Beautiful 5-Color Fluorescent Rock - Franklin, New Jersey

Contributed by: Chris Clemens
Date: Apr 29th, 2026
Locality: Franklin Mine, Franklin, Sussex County, New Jersey, USA (See on Mindat)
Size: 53 x 42 x 64 mm
Weight: 273 g

Description:
This is a beautiful rock from the Franklin mine, Franklin, Sussex County, New Jersey, that shows a spectacular 5-color fluorescent response under shortwave UV. This multi-mineral assemblage contains bright yellow fluorescing esperite, bright green willemite, blue, fluorescent hardystonite, and minor amounts of red fluorescent calcite and orange clinohedrite. This rock also contains a significant amount of black, non-fluorescent franklinite.

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

Fluorescence under shortwave UV light.
Fluorescence under shortwave UV light.
Normal light.
Normal light.

Summary of luminescence responses:

Esperite (Mindat) (RRUFF)

  • Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Yellow
Hardystonite (Mindat) (RRUFF)
  • Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Blue
Willemite (Mindat) (RRUFF)
  • Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Green
Calcite (Mindat) (RRUFF)
  • Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Red
Clinohedrite (Mindat) (RRUFF)
  • Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Orange

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