Roeblingite from the Franklin Mine, NJ

Contributed by: Simone Conti
minID: K7R-M6X
Date: Sep 17th, 2026
Locality: Franklin Mine, Franklin, Sussex County, New Jersey, USA (See on Mindat)
Size: 2 x 2 x 2 cm
Weight: 12.3 g

Description:
A fragment of a roeblingite nodule, showing its characteristic porcelaneous, or coconut-like, texture in daylight. It fluoresces dim orange under shortwave UV light. I feel like the fluorescence is a bit weaker than the usual, but I don’t have that many samples to compare to…

Fluorescence under shortwave UV light.

Normal light.

Summary of luminescence responses:

Roeblingite (Mindat) (RRUFF)

• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Orange