This a lot of two specimens, both analyzed. (See the “Analysis” tab.) The first specimen (2.0 x 3.5 x 1.2 cm) has small pyrophanite crystals (not analyzed) with “smectite group” (analyzed). The second specimen (1.4 x 1.9 x 1.1 cm) has numerous, but very small, crystals of mckelveyite-(Y) – very rare at MSH (analyzed).
The first five photos are for the pyrophanite specimen. The pyrophanite crystals are <= 0.7 mm in diameter. The same crystals are shown in the first two pairs of photos (FOV 2.0 x 2.7 mm and 2.3 x 2.6 mm). The pyrophanite crytals are associated with calcite and golden flakes of “smectite group” (specific species undetermined ). Note: The grunge on the pyrophanite has been cleaned up since I took the photos, but the crystals are more difficult to photograph now because they are so reflective.
The last three photos are for the mckelveyite specimen. Mckelveyite-(Y) is a very rare mineral at MSH. Moreover, it is impossible to distinguish mckelveyite visually from other donnayite group minerals found here. It is often thought that yellow samples are mckelveyite or donnayite, but that has proved to be a useless rule based on the analyzed specimens that I have seen. In general, even qualitative EDS does not suffice. (For one thing, the donnayite group minerals generally form syntactic intergrowth with each other and with synchysite-(Ce).) In this case, however, the tiny gray “mushrooms” give a pretty good match for what one would expect for mckelveyite-(Y), so I have labeled the specimen accordingly.
Most (but not all) of the mckelveyite crystals are shown in the two photos (FOV 2.2 x 2.8 mm). Unfortunately, the crystals are very small (< 0.25 mm in diameter) and sit on “less-gray” natrolite, so they don’t make for very impressive photos. But they are visible enough under a scope at 30-50X.
Combined shipping weight is ca 3.0 oz (85 g). Outside the USA, the stated postage and packing rate applies up to a total weight of 8 oz (225 g). If you wish to combine with items from future auctions, you must let me know.
Within the USA, there is a nominal increase of $0.20 for each additional ounce. Above 13 oz, I will use Priority Mail. Up to 16 oz, the “own box” Priority rate is $9.25 (including packing).
