This is a small and frankly, unimpressive, looking specimen. But there is much more than meets the (naked) eye. Specifically, it features small laths of the uncommon zincian variey of kupletskite plus pseudomorphs of ancylite after petersenite-(Ce) (or perhaps rémondite-(Ce) – there is no relict material that could be used to ID the precursor even with WDS). In addition, under SEM, one can see tiny crystals of monazite-(Ce) sprinkled on the kupletskite as well as on very fine needles of agirine or a sodic amphibole. Monazite–(Ce) also forms an external crust (epimorph) on the ancylite pseudomorphs. Moreover, all these species have been verified via qualitative EDS – to the extent that that is possible. See the “Analysis” tab. Details are provided with the photo descriptions
All of these features/species are visible in the first pair of photos (FOV 2.5 x 3.6 mm). The largest kupletskite lath (upper right) is 1.25 mm long. One of the monazite/rhabdopahane ancylite PSMs is at left-center. Tiny (0.2 mm) monazite encrusted aegirine (or amphibole) needles can be seen at bottom-center. The Zn peak in the kupletskite scan (#278) may not look significant, but Zn is fairly hard to detect, so it implies substantial enrichment. In fact, some of the Zn even shows up in the scan (#279) for the tiny monazite crystals on the kupletskite. (These are not really visible in the photo. You need SEM.)
Qualitative EDS can’t really tell monazite-(Ce) from rhabdopahne-(Ce). It makes sense to label the crystals on the kupletskite as monazite-(Ce) (scan #279), because rhabdophane –(Ce) doesn’t form crystal larger than a few 10s of microns. (All the rhabdopahane “crystals” at MSH are PSMs.) I labeled scan #281 the same, because it is probably the same stuff. The yellow crust on the ancylite PSM is more iffy, so I left in undecided.
The second pair of photos (FOV 6.6 x 4.1 mm) is a broader view showing more of everything. The interior of one of the larger ancylite PSMs can be seen on the far right. Note that there are ancylite crystals not only in the hollow interior, but also some larger ones on the outside.
The interior of this PSM is also shown in the next pair of photos (FOV 4.3 x 6.8 mm). It is really just a mess. EDS (#304) shows it to be intermediate ancylite-(Ce) – calcioancylite-(Ce). The Ca peak looks somewhat higher than the Sr peak, but Ca is easier to detect than Sr, so that can be misleading. A fairly reliable rule for visual identification of ancylite vs calcioancylite is that if it replacing something, there is a good chance that it is calcioancylite. But this case is too close to call. (All other "rules" have been shown to be useless.)
Single item shipping weight (with TN case) is 3.3 oz (94 g). For shipments outside the USA, up to a total weight < 8 oz (225g), this can be combined with items from this or other auctions for the same postage.
Within the USA, postage increases by about $0.20 per ounce. Above 13 oz, I will use Priority Mail (approx $9.25 including packing).
