There are two (or more) fluorescent minerals here. One is vlasovite, which in ambient light looks glassy and colorless to slightly pinkish. The other is a cream yellow chalky mineral that occurs mostly as a crust/coating on vlasovite cleavages/partings. Probably this is gittinsite, but the label doesn’t say so, and I’m no expert on Kipawa.
To my naked eye, the SW response of both minerals seems similar, the vlasovite being a fairly bright cream yellow, whereas the gittinsite seems somewhat more greenish (as reported by others). However, my camera thinks that only the “naked” vlasovite fluoresces yellow, whereas the encrusted areas fluoresce quite greenish (note especially the “back” side child UV photo). There is a similar LW response, but only from the gittinsite. Given that I had to use a very long exposure (15 sec), I’m not sure I trust the camera response.
In any case, the photos do show that the stuff fluoresces – in one or more colors. The vlasovite grain (~ 1.2 x 0.7 cm) on the far left in the first two photos (and on the far right in the “back” side photos), is particularly bright. There is a close-up of about 6.5 mm of this grain in the fifth photo. (Note the good cleavage.) A close-up of some gittinsite is in the last photo.
According to Gittins, gittinsite occurs as “radiating sheaves of prismatic crystals 0.1-0.3 mm long”. I see no such structure here. But this is the stuff that my camera thinks has a green fluorescence – as reported for gittinsite by others. Note also the “naked” pinkish grain of vlasovite (upper left).
Note: According to the Handbook of Mineralogy, it is altered vlasovite that fluoresces brownish yellow. That doesn’t seem to be the case here. Note also that this specimen has no eudialyte. Instead, it is the type where vlasovite is embedded in feldspar. The black stuff may (or may not) be the “potassian magnesio-kataphorite” (of Gittins et al).
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