Nasonite & Prehnite from the Franklin Mine, NJ

Contributed by: Simone Conti
minID: Q9X-L31
Date: Sep 18th, 2026
Locality: Franklin Mine, Franklin, Sussex County, New Jersey, USA (See on Mindat)
Size: 4 x 3 x 4 cm
Weight: 78.8 g

Description:
A soup of Franklin minerals. Mostly nasonite and prehnite, I think mixed together, fluorescent yellow/grey/violet under shortwave UV light. Under shortwave UV you can distinguish two intermixed phases: one more yellow, one more violet. By Raman spectroscopy, it looks like both contain both minerals. These two phases can also distinguished in daylight, if you pay enough attention. Together with nasonite and prehnite, there are veins of red axinite-Mn, some orange clinohedrite with orange afterglow, and some green willemite. Some non fluorescent garnet finishes the composition. There are some other colors under UV which I did not identify, or that are are to distinguish from the rest.