There have been several posts in our Facebook Group (https://www.facebook.com/groups/fluorescentminerals) recently identifying some of the mystery minerals found in pieces from Afghanistan over the past couple of years. This area yields a large variety of fluorescent minerals, most discovered without a light - by purchasing on Ebay or FB. To my knowledge no one has yet brought a SW light directly to the mines. Once that happens I predict some amazing minerals will be brought to market. This blog post archives some of these IDs. Thanks for Mike Crawford, Ludo Van Goetham, and Daniel Montero for their work in ID'ing these minerals.
Mike Crawford Over the years, I have acquired several Afghan fluorescent specimens that contain a mineral that has unusual fluorescent properties. I finally sent chips from 3 hand samples to Attard Minerals to get XRD identification. I believe that XRD is one of the best methods for mineral identification. It is more expensive than other methods, but the results are very reliable. I highly recommend Attard Minerals for XRD analysis. I was very pleased with the service. XRD identified the mineral in all 3 samples as Forsterite (MgSiO4). The Afghan Forsterite has a weak blue-white to pinkish-white glow in LW. If you sweep the light from a Convoy flashlight across the Forsterite, it flashes red. see the attached video. Forsterite glows yellow to yellow-brown in SW light. If you hold the SW light close to Forsterite for at least 60 seconds and turn off the light, Forsterite has a dim, long lasting red afterglow. The mineral has to be charged in order to see the red afterglow. This is the only mineral that I am aware of that has a persistent red afterglow. The pictures show 2 of the rocks used for the XRD analysis. The first rock contains Forsterite, Hackmanite, and minor green Diopside. The first picture shows the afterglow of the Hackmanite (white) and the Forsterite (red), The next photos show the rock in SW, LW and white light. The second rock contains blue Lazurite/Hauyne that is non-fluorescent, Forsterite, Phlogopite, and an unknown light blue SW fluorescent mineral. Maybe I will get that one analyzed next time. The photos show the Forsterite afterglow, SW, LW and white light. The last video shows the Forsterite flash with a Convoy. The XRD analysis also identified the mineral Kinoshitalite in rock 2. The chips I sent for analysis also contained traces of what I thought was Phlogopite, instead the results suggest another phyllosilicate, Kinoshitalite. The left side of rock 2 in the pictures may be Kinoshitalite (Ba Mg3 Al2 Si2 O10 (OH)2). Solve one mystery and create another.
What a pleasant surprise, one of my guesses was fosterite when I was making a market in these. But dropped it after I bought a couple of specimens labeled as such that didn't glow. Good work! Mike Crawford I also have specimens that have white tabular crystals that were labeled as Forsterite that do not glow. The crystal shape resembles the glowing Forsterite crystals. They may be Forsterite without activators. .
Daniel C. Montero Thank you very much for this, I really wanted to get out of doubt with Forsterite, great news that what we called massive phlogopite is Kinoshitalite Ludo Van Goethem I have similar pieces. The white phase can be forsterite, but I also found a white phase composed of a mixture of phlogopite and diopsid. (all SEM/EDX analysed). The diopsid/phlogopite mix sometimes is coloured pink and shows a red fluorescence due to … See More Ludo Van Goethem Kinoshitalite: was it also identified via EDX or XRF besides XRD ? Has it the same fluorescence as phlogopite ? If the Ba content is confirmed, then I should check all my phlogopites. Up til now, I only found phlogopite via EDX, but often mixed with ot… See More Ludo Van Goethem Mike Crawford good idea. It’s a brittle mica, not to be expected there, but barite is described in Koksha, so there is barium
A couple more XRD results of my Afghanistan collection. The matrix of many specimens contains a white glowing mineral in SW light. XRD identified this white glowing mineral as Diopside in both samples that I submitted for analysis. The first set of pictures shows a vein of Afghanite (orange) and Marialite (yellow). The vein has been acid etched to remove Calcite. The etching exposed patches of the Diopside matrix that glows white. The first picture is fullwave (LW MW + SW). The second picture is the white light picture. The third and fourth pictures are a side view of the specimen showing the matrix in SW and white light. Diopside is the mineral responsible for the white fluorescence.The last 3 pictures show a second specimen sent for analysis. The pictures are white light, LW and SW. The circled area on the white light picture shows the location of the chip sent in for analysis. XRD identified Marialite and Diopside in the chip. The Marialite glows yellow in the LW picture. Diopside glows white in the SW picture.
Daniel C. Montero · Recently I have seen for sale some specimens of Afghanistan with a yellow response under LW of a massive mineral "unknown" I have this in my collection. This unknown yellow LW changes to whitish SW so it differs from the crystals of marialite that under SW are also yellow. Any idea what mineral is? LW-SW-NL.
Mark Cole Very common to have massive phlogopite in matrix, but that's usually a bright yellow SW, and often a dull color LW. The zoning of the fluorescence is strange - it has a sharp cutoff where in the white light pic I don't see a difference in color. Any … See More Daniel C. Montero No Phosphorescence.
Glenn Waychunas Could be scapolite. Yellow LW but can be anything under SW because Fe create a red emission, you can still get some yellow, and there can be blue emission---all together you get some kind of white. Daniel C. Montero Unknown resolved ... the yellow Fluo belongs to Marialite, this was also my first impression but the white fluorescence confused me. With Mike's XRD results it can be deduced that this sample contains massive Marilite and Diopside with Afghanite and ph… See More
Ludo Van Goethem Further on the interesting minerals on afghan pieces. First pic: white epitaxy on a lazurite background. The white epitaxy consisted of phlogopite containing tiny pieces of Cr-spinel (spectrum included, black: total, red lazurite subtracted, yellow Cr-spinel compared). It also contained a white to pink phase. The pure white was forsterite. The more pinkish a mixture of phlogopite and diopside (SEM pic). A decomposed spectrum shows the orange fluorescence to be a mixture of Mn2+ in phlogopite and diopsid. The orange fluorescing needles (2nd pic) turned out to be an afghanite phase grown on lazurite. It took me a year to solve the puzzle. All compositions EDX confirmed.