A Fluorescent Classic- Calcite and Willemite from the Franklin Mine, Franklin, New Jersey
Contributed by: Chris Clemens
minID: GTK-9R3
Date: May 19th, 2026
Locality: Franklin Mine, Franklin, Sussex County, New Jersey, USA (See on Mindat)
Size: 7.3 x 6 x 11.2 cm
Weight: 982 g
Description:
This is a classic fluorescent specimen from the Franklin Mine, in Franklin, New Jersey- the self-proclaimed "Fluorescent Mineral Capital of the World". This piece contains the two most commonly occurring, and among the most brightly fluorescent minerals from Franklin - calcite and willemite. Viewed under shortwave UV (254nm), the calcite shows a bright orange/red response, and the willemite fluoresces bright green. Of historical interest, this piece contains the three primary ore minerals that were sought after by the zinc mines of Franklin - willemite, and non-fluorescent black franklinite and red/brown zincite.
Originally posted by Chris Clemens on Nature's Rainbows in 2016.
Summary of luminescence responses:
Calcite (Mindat) (RRUFF)
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Red
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Green