Specimen Notes
Occurrence - The specimen apears to be a somewhat compacted volcanic miarolitic ejecta fragment having many large voids and cracks throughout it.
The most common mineral present has the characteristics of a light blue-grey Afghanite or another of the feldspar minerals. Other minerals identified are: Biotite mica; pyrite (in weathered, iron oxide stained, pyritohedrons); Smoky Quartz; Uranpyrochlore; Danburite (?), Nosean; and Hydroxylapatite (approximately 1.5 cm away from the Piergorite). Several other minerals, not identified as yet, are also found in quantity.
In image (001a) are several other Piergorite crystals, but they are difficult to identify against the clear mineral having bubbly striations. Microscopic examination shows them to be distorted gas inclusions and not fractures, likely due to dissolved gases coming out of solution as the mineral crystalized from the melt. This mineral is believed to be monoclinic as it presents right angles visually on two sets of faces, but the plane of the gas striations is not parallel to either of these two faces, see image (001a). The effect is very similar to that seen in glass that has been foamed and stretched by an admixed carbonate when vitrified, only this mineral is definitely crystaline.
Crystals - The Piergorite occurs in a simple monoclinic form. Image (001a) is of four crystals. The sharp angular appearance is is due to the fourth crystal being angled at approximately 78.5° to two of the other crystals, interacting optically with them to give them a highly angled appearance. Looking carefully, the faint outline of the right crystal's termination can be seen, appearing as a thin fiber. The termination of the left crystal can be seen just beyond its apparent 'point', as can be seen the termination of the fourth crystal.
In image (001a), one of the 'L' shaped twins that Piergorite is known for can be seen. This third crystal of the four is doubly terminated, with a scepter growing off of one end of it.
Image (001b) shows a flat plate of Piergorite growing on twinned octahedral crystals of Uranpyrochlore. To the left of these is a crystal of Nosean.
Image (001c) shows a spray of Pirgorite crystals radiating from a point on the surface of a quartz crystal. Above them is a second quartz crystal. The Piergorite crystals are so small in diameter, relative to their length, that they appear fiberous. The black mineral in the lower left quadrant is unknown, and is a pseudo-hexagonal prism. On its surface, where the cellulose fiber is locate, are several thin sheets of biotite mica. Approximately 7 mm to the left and down, well outside the image, is a cluster of Biotite mica crystals. The druse of tiny crystals are tightly bonded to the surface of all the minerals, and are not detritus. There appears to be at least two different minerals. Neither is believed to be quartz.
Image (001d) shows a crystal of Nosean. In the center of the lower right quadrant are a cluster of three readily visable Piergorite crystals. Around them, visable with close inspection, are several other Piergorite crystals and plates. Above them are several plates of Piergorite that are not readily identifyable except by manipulating the specimen for optimal lighting for reflection.
Appearence - All the crystals of Piergorite are under 0.5 mm in length. Several of the plates approach 1 mm in diameter, all being extremely thin, on the order of several micrometers. There does not seem to be any relationship as to the occurrance of plates and crystals, other than that while they occur close together, they do not grow intermixed with each other.
Diaphaneity - The Piergoriet crystals vary from totally clear and transparent to translucent. When transparently clear, they can seem to disappear, as in image (001a), where only the edges of the crystals are visable. With one crystal, its edge, just visable to its right, appears as a thin thread under the microscope, and was mistaken for a long, straight, fiber.
In this same image is present a very thin, clear and transparent plate of Piergorite that is not visable in the image due to these properties. The image of the bubble striations in the unknown mineral are unaffected by its presence.
The Piergorite crystals by the Danburite crystal in image (001d) were all translucent. There is some iron staining in that area, and it is not known if this, the Danburite, or one of the other minerals present, is the cause. The fiberous appearing spray of Piergorite crystals in image (001c) are transparently clear, and are on the opposite side of a crystal just below the bottom of image (001d).
Almost all of the plates observed were also transparently clear. The plate on the Uranpyrochlore in image (001b) was one of the few plates away from the Danburite in image (001d) that were slightly cloudy and translucent.
Luster - The crystals and plates that were transparently clear showed no luster unless illuminated at just the perfect angle, where the reflection was adamantine. This indicates the surface of the crystals' pinacoid to be nearly, if not actually, optically flat.
The crystals and plates that were not transparent had a dull luster, much like water vapor fogging a pane of glass. This is best seen in the three crystals in images (001b) and (001d).
Cleavage and Fracture - None of the crystals appeared to have been broken, so this is not known. The crystals are apparently quite strong.
Fluorescence - The Piergorite is non-fluorescent. Several of the other minerals, like the Danburite/Nosean, showed a very faint pink fluorescence under long and short wave ultraviolet light, observable only through the microscope in a blacked out room.
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Specimen Physical Properties
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cm |
cm |
cm |
| Weight: |
x grams |
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| g-Radiation Level: |
cmp |
msieverts |
background: 20 cpm |
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