Specimen Notes
The Znucalite appears to have been deposited by two different mechanisms. The first is that it was created by chemical reaction elsewhere, and deposited as a slurry. This results in the smooth, flowing deposits that appear similar to paint that was applied too heavily. The second mechanism is the deposition of Znucalite from solution, forming microcrystals.
Early Stage Deposits - There are two general types of slurry deposits. The early deposits appear to be a mixture of rock dust and grit bonded together into a solid mass by Znucalite acting as a cement, as seen in -001ba, -001bc, -001bd, -001bf, -001bh, -001bn, -001bo. Tiny crystals of Znucalite can often be seen as a druse on the surface of many of the lighter colored (ash gray) concretion deposits, giving them a kind of visual sheen. These deposits range in color from a very light ash gray (-001bc), to a charcoal gray (-001b), to nearly black (-001bf).
The lighter colored concetion deposits appear to be rock dust bonded with Znucalite. The charcoal gray (-001bc) deposit appears to be so due to both dark colored mineral inclusion and staining by another mineral. The nearly black deposit (-001bf) appears to be so primarily from heavy staining by another mineral co-deposited with the Znucalite bond. Znucalite can be rather easily stained by other minerals, as can be seen in images -001bk and -001bm. In -001bk, a mineral central to the stain appears to be disolving, and possibly chemically reacting, to stain the surface of the Znucalite deposit. In -001bm, the Znucalite is seen to be more seeply stained, but the stain is not as intence, being diluted by the Znucalite.
Color - The second form of Znucalite deposit is pure, or nearly so, Znucalite. The color of these deposits is a light bluish-white, as seen in nearly all of the images of this type of deposit. In images -001ba and -001bb, a yellow tinge or yellowish-white color can be seen. As these deposits are not totally pure, and do not appear to be crystaline, it is believed that the yellowish-white color seen here, at least, is due to impurities deposited with the Znucalite. At several locations in -001bc and -001bd -001bm, the Znucalite has acquired a yellowish-white stain. It is the ease of staining and the nearly pure crystaline deposits that indicate that the true color of this mineral is bluish-white.
Crystals - Almost all of the observed crystals of Znucalite are all under 0.01 millimeters in length. The Znucalite crystals that occur as a druse on the ash gray concretion layer are all smaller than this, and can only be observed (at 30X magnification) as barely detectable speckles. The largest observed crystals are only slightly larger than 0.01 mm, and all that can be stated is that they appear to be acicular in form.
Some of the crusts observed in cross section, particulaly thos that have a polished or pearly luster, consist of many parallel crystals that have grown perpendiular to the plane of the crust, and their length is approximately the thickness of the layer of crust. Almost all deposits are in the form of layers.
Luster - The luster of the pure (rock dust and grit free) deposits of Znucalite is very variable, but varries little across a single deposit layer. Most common is a very smooth, non-glossy surface that appears somewhat earthy under a microscope. Almost as common is a polished surface that appears almost adamantine under a microscope. This layer, where it appears in cross section, is composed as many parrallel crystals growing through the thickness of the layer. Most rare is a pearly, almost opalescent, luster that has a 'pebbly' appearence under the microscope. This is seen in only a few small exposures, and appears to possibly be from a single deposited layer of limited size.
Specimen Orientation - The orientation of the specimen is believed to be as stated mainly due to the sheet-drop pattern, seen in viscus fluids dripping from the bottom of a flat horizontal surface. This drip pattern is best seen in images -001bh, -001bi and -001bj.
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