Apatite (johnbaumite?) with calcite, shown under SW UV.

The pink in this photograph is calcite, which tends to blend in with and obscure the orange fluorescence of the other mineral. Based on the associations and the fluorescent color, I'm now thinking johnbaumite or (a remote possibility) turneaureite. At the very least it's probably an arsenian fluorapatite. I think these three minerals can probably occur together in a mixture that would be impossible to determine without instrumental analyses. Maybe such a mixture is what we have here in this specimen.

Franklin collectors used to call this mineral "svabite", which is chemically similar to johnbaumite {Ca5(AsO4)3(OH)} and turneaureite {Ca5[(As,P)O4]3(Cl)}. True "svabite", I've learned, does not really occur at Franklin, even though the other arsenic-bearing apatites do occur there.

I had to break open literally hundreds of pounds, if not a couple thousand, to find the specimen pictured above. I can't imagine how many hot days I spent down there in search of this mineral (whatever it is). It is not at all common on the Buckwheat Dump. Judging from the field trips to the Trotter Dump, it is rare there, too. I plan to keep looking, though.

The photo needs to be replaced with a higher-res version.  A retake of this photo is somewhere near the bottom of a very long to-do list.

Photo index


Photos, text, and other site contents are subject to Copyright.    
All rights reserved.