This specimen features excellent examples of three MSH type locality species, adamsite-(Y), thomasclarkite-(Y) and niobokupletskite, all of which are quite rare here. (The niobokupletskite was confirmed via qualitative EDS - see the “Analysis” tab.)
Thomasclarkite and niobokupletskite have not been found elsewhere. Adamsite is known from only two other localities. On this specimen, the adamsite is in the form of bladed crystals, some with good terminations. More commonly, adamsite occurs as radiating fibers or as flakes on altering shomiokite-(Y).
A few “fuzz-balls” of franconite, another very rare mineral, are also on the specimen. In addition, there are “flaky” PSMs of synchysite-(Ce) with rhabdophane-(Ce). PSMs of synchysite-(Ce) after petersenite-(Ce) were fairly abundant in the Poudrette pegmatite, but in this case the precursor appears to be an unidentified blocky mineral.
The first pair of photos (FOV 3.6 x 2.4 mm) shows some of the best terminated adamsite, along with two franconite balls (1.1 mm). The raggedy off-white stuff in the lower right corner is one of the synchysite/rhabdophane PSMs.
The second pair of photos (FOV 2.3 x 3.7 mm) shows more terminated adamsite, along with the same two franconite balls and one of the PSMs (in the center).
The next photo (FOV 6.7 x 4.5 mm) is a broader view of the main adamsite cavity, showing more of the adamsite.
The next photo (FOV 2.3 x 3.5 mm) shows bladed adamsite to 2.9 mm in another cavity. In this case, most of the adamsite grew wall-to-wall, so there are only a few terminations. The dark green crystals are aegirine. There are some other cavities with smaller adamsite crystals on the specimen.
The next pair of photos (FOV 3.7 x 2.3 mm) shows the thomasclarkite-(Y). The main group spans 1.1 mm. Note: There is some not-too-pink rhodochrosite/siderite on the specimen that has a superficial resemblance to the thomasclarkite. But a careful look will reveal differences in the habit. Another of the synchysite PSMs is seen at center-right.
The next photo (FOV 3.7 x 2.5 mm) shows one of the two main areas of niobokupletskite on the specimen. The lighter brown niobokupletskite grows on ordinary dark kupletskite (not analyzed), some of which is terminated.
Single item shipping weight (with TN case) is 3.2 oz (91 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 for total weights up to 13 oz ranges from $4.25 to $6.50 (including packing etc) regardless of destination. Above 13 oz, I will use “own box” Priority Mail. The rate, including packing, varies by destination from $7.25 to $9.50.
See my updated “Shipping Policy” for details.
