Apple Green Willemite, Franklin, New Jersey
Contributed by: Chris Clemens
minID: U0Y-572
Date: Apr 20th, 2026
Locality: Franklin Mine, Franklin, Sussex County, New Jersey, USA (See on Mindat)
Size: 86 x 59 x 100 mm
Weight: 866 g
Description:
This is a variety of willemite from Franklin, New Jersey called "apple green willemite" for its, well... apple green color. This is one of the brightest fluorescing minerals when viewed under shortwave UV, producing a brilliant green response. It also shows a phenomenon known as daylight fluorescence, meaning that when viewed in daylight outside, the UV component of sunlight activates the green, fluorescent response which is visible as a brightening of the green color of the specimen. The fluorescence of willemite under longwave UV (365 nm) is highly variable, but this piece shows a bright green response.
Originally posted by Chris Clemens on Nature's Rainbows in 2020.
Summary of luminescence responses:
Willemite (Mindat) (RRUFF)
- Fluorescence under Longwave (365nm LED) UV light: Green
- Fluorescence under Midwave (305nm Lamp/Mercury) UV light: Green
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Green
- Fluorescence under Daylight: Green