MSH offers a bewildering variety of rare species, most of them exceptionally well-crystallized. To add to the fun, there are countless variations in habits and associations. Examined closely, almost every specimen will reveal something surprising. This specimen is a good example. At first glance, it seems to be a specimen of very good, but not unusual, petersenite-(Ce) associated with “arfvedsonite” (probably “plain vanilla” arfvedsonite – this was not analyzed). But under a scope, one sees that the petersenite is accompanied by bent “noodles” of elpidite (verfied via EDS – see the “Analysis” tab), that the arfvedsonite is apparently epitactic on aegirine, and that there are tiny crystals of apatite (also verified via EDS) of an unusual (for MSH) honey color in parallel, possibly epitactic, growth. MSH is the TL for petersenite-(Ce).

The first pair of photos (FOV 3.1 x 2.2 mm) shows an elpidite crystal 2.8 mm long. Despite being bent like a wet noodle, the basic orthorhombic symmetry of elpidite is still evident. An orthorhombic wet noodle!

The second pair of photos (FOV 4.0 x 6.7 mm) shows some of the pinkish, unaltered petersenite-(Ce) on the specimen. At the bottom of the photo is a white prsim of elpidite, 2.3 mm long, of much more typical appearance. In the center is an example of “arfvedsonite” penetrated by aegirine. The relationship appears to be epitaxy, but I’m no expert on this subject.

The next photo (FOV 3.4 x 2.25 mm) is a close-up of the elpidite crystal shown in the previous pair of photos. The orthorhombic symmetry is quite evident under a scope. (The elpidite was analyzed both because of the strange bent shape exhibited by some crystals and the visual similarity to nenadkvichite of crystals such as the one in this photo. The two EDS scans are vistually identical, and both indicate “elpidite”.)

The next pair of photos (FOV 3.6 x 2.4  mm) is a close-up of another example of arfvedsonite epitactic (?) on aegirine. The largest visible aegirine needle is 1.2 mm long.

The next photo (FOV 2.3 x 3.3 mm) shows another bent crystal of elpidite (0.85 mm) at the bottom with some of the honey-brown apatite at top. The apatite – almost certainly fluorapatite, the only apatite currently on the MSH species list – looks tabular in the photo, but that is an illusion. Viewed at higher maginificatio (50-60X), the typical hexagonal shape becomes evident. (Due to the limit of 10 photos, I was not able to post this.) The aggregate looks tabular because the crystals are growing in parallel – something that is very unusual for apatite at MSH (at least in my experience). The apatite spans 0.85 mm.

The next photo (FOV 3.7 x 2.3 mm) shows more of the apatite, again in parallel growth. Next to this area is more apatite in jumbled growth (not shown). The individual apatite crystals are only ca 0.2 mm long. You will need at least 30X to appreciate this stuff. The parallel growth suggests epitaxy, but is hard to understand why apatite would be epitactic on microcline. It seems more likely to me that this parallel growth is a relic of some previous crystal – perhaps a larger apatite.

Single item shipping weight is 3.7 oz (105 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 ($9.25 including packing).