Fluorapatite, calcite and willemite from Franklin
Willemite - green
Calcite - red
Fluorapatite - orange-brown
Andradite - non-fluorescent
Franklinite - non-fluorescent

This came from the Buckwheat Dump during the fall, 1999 night dig. The orange-brown fluorescent material is most likely fluorapatite {Ca5(PO4)3F}, possibly with some arsenic content, which would make it "arsenian fluorapatite". It does not fluoresce as strongly as the surrounding minerals, making it very difficult to spot unless you search carefully.

Samples of this mineral have appeared locally on the market as "svabite" {Ca5(AsO4)3F}, but analyses have reportedly shown it's not svabite.  The fluorapatite from Franklin may very well be something like Ca5[(P,As)O4]3F, however. Then again, it may also grade into johnbaumite, in which OH takes the place of the F.

The associations include willemite (green), calcite (reddish), franklinite (black in visible light), and andradite garnet (brown in visible light).

Photo index

Site content and photos are copyright 2007-2009, njminerals.org