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[rocknut]

This piece came from a recent find at the Bingham mine. Reportedly there was only one small pocket. Someone have seen a color like this in fluorite before? Someone know what chemical(s) causes it?

I took it with pocket camera and backlit the fluorite with halogen. No color enhancements.

Thanks for the help.

[Gail]

I recently bought a new piece from the mine from Ray DeMark, one of three partners of the mine. He never mentioned such a find, but am due to call him tomorrow to return his call to me. I will ask about it.
We bought a fabulous piece he had just pulled out a few weeks ago.

I have mined there, I never saw such colour but then again, who knows what is lurking in the mines?!
I uncovered a pocket of crystals the first time there and harvested quite a few blue to purple blue fluorites with galena and quartz.
Linarites were also prevalent.

[Jordi Fabre]

In a special part of Berbes, the area named Los Cobayos (or La Paredona) some Fluorites appeared with a very similar color to the violet of this one. Not bicolor, but pretty much similar of the central color of your specimen.

About the color on Fluorites, it is usually generated by a color centers phenomena and not for chemical reasons.

Jordi

[John S. White]

The following is quoted from Mineralogy, by Berry, Mason and Dietrich, 2nd edition, 1983, W. H. Freeman &Co.:

Lattice imperfections (defects) within minerals that are colorless, or nearly so, may also give exotic color to their containing minerals. Defects that are responsible for color are widely referred to as color centers. Those dependent on the presence of an extra electron and those involving the absence of a normally present electron have been termed electron color centers and hole color centers, respectively. This color production also involves the excitation and shift of unpaired electrons, and the consequent energy shifts, which, in turn, cause selective absorption and transmission of certain wave lengths of the visible part of the electromagnetic spectrum. Examples are purple fluorite, in which unpaired electrons may be entrapped in positions normally occupied by fluorine ions, and smoky quartz, in which hole color centers are created by the presence of aluminum that replaces silica and is electronically neutralized by the presence of an alkali element or a hydrogen ion.

[rocknut]

Thanks Gail,

I'm not as familiar with New Mexico fluorites as you, but I did grow up in Dallas and have seen quite a few over the years and I've never seen one like this either. They referenced the fish stick pocket so maybe that will help. Let me know what you find out.
Thanks