Identity HelpStrange Lime Green Mineral on Wulfenite from Los Lamentos.
I recently noticed this Lime Green Mineral on the edge of one of my Wulfenite's from Los Lamentos, and I'm not quite sure what it is. My best guess would be its Mimetite, but I've never really seen it like this; especially from this locality.
ANY IDEAS? :-S
Much of the descloizite there is greenish...usually not quite that green but I've seen it from green to rootbeer to almost black. 
Pyromorphite is on the list from Los Lamentos, so it is possible. However, since it is on wulfenite, I think it might be mimetite (not on the list). I tried zooming the photo, but it loses its resolution at the higher magnification. Under a microscope or with a loupe, can you get a feel for the crystal system. Hexagonal, monoclinc, etc.? Can you do a closed tube test? A bit of the mineral with a little powdered charcoal will produce a black sublimate or arsenic on the cooler wall of the upper tube if it is mimetite. It takes very little to do it. 
"Much of the descloizite there is greenish."
Maybe it could be mottramite then. 
Unfortunately I don't think any conclusion can be reached without analysis. Ive never seen Descloizite that lime green before. I don't think thats it.. I know that Mindat doesn't list Mimetite as a Mineral that occurs from Los Lamentos, but that would still be my first guess, but maybe it could be something like Willemite? Ive seen Willemite come in a green color before (Not quite that color green though) and its on the list for this area.
Also, Ive tried looking at it under magnification and I can't determine the crystal structure. The crystals are just too small, and all I have is a hand lens. I will try to take a better picture tomorrow morning. Maybe that will help. Mottramite (not on the list) . . . interesting and reasonable thought, Uwe. 
It doesn't look much like wulfenite from Los Lamentos. Rock Currier: Its definitely Wulfenite from Los Lamentos. I purchased the specimen from Evan Jones. Plus, I have a few other pieces of the "Candy Orange" colored Wulfenite's from Los Lamentos. Its not that uncommon. Ive just never come across this lime green mineral on any of my other Ahumada Mine Pieces.
CHECK OUT THIS PICTURE FROM THE LOS LAMENTOS GALLERY. This picture says the Wulfenite is surrounded by Micro-Mimetite Crystals
http://www.mindat.org/photo-3783.html
Ian, if you're convinced, so be it.....but you don"t have to Yell!!! I'm not convinced......
Don I didn't mean to sound like I was yelling or anything like that. It was just the conclusion that I had come to last night. HOWEVER, After doing a little more research and asking a few other (Smarter ;-)) people, I think I was wrong about it being Mimetite.
I was talking to my Grandpa about what this strange green mineral might be and he said that he had a specimen that was exactly like that with even more of the "Mystery Mineral." After looking at it under magnification, Im pretty sure its Pyromorphite. Apparently, the famous collector Miguel Romero discovered Pyromorphite w/ Wulfenite from Los Lamentos in the 1960's or 1970's. When I looked at my Grandpa's Specimen under a scope, I could see the Hexagonal Crystal Structure and then I was pretty convinced that it was Pyromorphite, not Mimetite. So for everyone who said its Pyromorphite, I think you guys are right! Great Job =]
I tried to take a few more pictures to post for everyone because my first 3 werent very good. I'll add them below.
Thanks Everyone! :-D
It would be nice to see an analysis before we get too excited, it could just be a visual ID. Admittedly, it does look like pyromorphite but I've seen too many supposed pyromorphites (especially from the Ojuela mine) that turn out not to be pyromorphite. I thought descloizite because I have seen greenish descloizite from Los Lamentos but not quite so bright as Ian's specimen. Mottramite makes sense to me as well. Pyromorphite makes even more sense but I've learned to be overly skeptical about pyro claims I guess!
In any case, it is a decent rock with superb luster and good color. Excellent photos by the way! Dana: I was skeptical about it being Pyromorphite as well. I hadn't ever heard of it coming from Los Lamentos; Let alone being associated with Wulfenite. Thats why I was convinced it was Mimetite (Even though the Mindat Directory didn't have Mimetite on their list of Los Lamentos.)
However, I just looked at the picture of Pyromorphite from Mapimi and it looks identical to the stuff thats on my specimen. It has that fine, fibrous look to it, and the color is an exact match. Take a Look:
I agree with rock, looks like Ojuela material, not Los Lamentos. I have literally hundreds of identical specimens in my inventory. The specimens are both from The Ed Over Collection. They are definitely from Los Lamentos; particularly the Ahumada Mine. Ive seen many other Wulfenites from Los Lamentos that look like these ones. The Wulfenite Crystals from Mapimi have a different look to them. They aren't the 'Candy Orange' Color, and they don't have the distinct cubic crystals like the specimens from Los Lamentos.
I am 100% sure this piece isn't from Mapimi.
Anyways, Thank you everyone for your input. This has definatly been an intriguing conversation!
Adios!
-Ian W.
