[Rockhounds] interesting fluorescent sphalerite - yellow, magenta, blue

[pmodreski at aol.com]

Hi, Rockhounds,


I have an interesting fluorescent sphalerite specimen (several small specimens, actually) to describe, and I wonder if anyone has any comments about (a) similar specimens you may have seen, and/or (b) any guess (by comparison to specimens you've seen) of where this might be from.


The specimens were among a batch of specimens (from multiple sources) that had been donated to the Colorado Springs club (CSMS) for the silent auctions at their show, which was last weekend.  So--no labels with the specimens, no locality identified, and no idea any more, who might have donated any given group of the specimens.  So all we have to go on is "what you see is what you got".


I posted a description of these to my friends on facebook yesterday, with one picture (not a very good one--when I have a chance with a "real camera" instead of my cell phone, I'll try to get a much better one), and here's what I said there:


"This post is for my serious mineral friends who are, still more, seriously interested in fluorescent minerals. Here's one of several small specimens that had been donated to the CSMS club for their silent auction (no label, no locality). They were composed of a banded mineral vein of galena and pale tan siderite, within which are (my best interpretation) thin layers of fluorescent sphalerite: first a yellow layer, then magenta, then fl. blue. Please pardon the out-of-focus image, it's the only one I have right now. It's quite striking! Anyone have any idea what the locality might be?"



The easiest way for me to share the photo is to give you this link that will take you to that facebook post of mine (anyone can access this, whether or not you have a facebook account):

https://tinyurl.com/flsphal


To recap what I said in the above post, the specimens were small pieces (and inch or two in size) of mineral veins in which the predominant (and avidently last formed) mineral was siderite (a crust or masses of pale tan intergrown crystals), and the earliest mineral layer appears to be mostly galena.  In between--and the thickness of the vein(s) is only about 1/2 inch--there are thin layers containing a fluorescent (LW) mineral that I'm pretty sure--from the fluorescence--is sphalerite.  The sphalerite--in very thin layers--is just about invisible without UV, but in longwave UV it fluoresces the colors I noted, yellow, magenta, and blue.  In some specimens, there is just a thin layer of yellow-fl. sphalierite.  Others have the yellow-fl. layer and beneath it (and slightly separated from it) an even thinner layer of magenta or blue-fl. sphalerite.  In just one specimen--the one I've pictures--we saw the three distinct layers: blue, then magenta, then yellow.  (I've seen all these colors in fl. sphalerite before (such as sometimes from Franklin/Sterling Hill NJ), and that's my main reason for presuming that the fluorescing mineral is sphalerite.


So, has anyone seen anything similar to this?  Any suggestions about a possible locality? (I "could" be from Colorado, but of course it could be from anywhere else, too.)  I guess I should also add--I was helping the club identify & label specimens for their silent auction, so most of these the we found in the "pail of specimens" got put out and sold at the auction.  I only kept a few, and a friend (Don Bray--who first found and showed me these fl. specimens) actually has the only one that I know of that clearly showed the 3 distinct fl.-color zones, which are shown in the picture.


I apologize again for the fuzzy picture, but it does show the color zones.  Another friend took a hopefully better photo which he'll send to me, and as I said, I'll try to get a sharper one (though maybe only with 2 color zones) myself, including a photo of the what the siderite vein looks like in daylight.


P.S., a day or two late, let me wish a HAPPY BIRTHDAY to one of our champ studiers of fluorescent minerals, Axel Emmermann, of course!  You (Axel) are a likely person who may have some comment on this.


Thanks & good wishes to all,


Pete Modreski