This is the second in a series of two danburites obtained from AJS Gems. This is a brief study, and a more formal and much more detailed study will be presented at a later date. The following is based on microscopic imagery obtained through darkroom conditions and illuminating as such.
There were some different artifacts found compared to the last one, but at the same time there were some others of like kind, and some artifacts that are just different and unique to this second specimen. Then again at a microscopic level, no two stones are going to be identical but they will have like characteristics.
This particular specimen is a Portuguese oval that is very well proportioned. There are no visible windows or extinction. They’re not ideal proportions, but the crown has been compensated enough with the shape of the pavilion to compensate for much of that. So all and all as far as colored gem stones go, this is nearly as good as you could expect on the cutting.
This particular specimen is by vendor documentation 9.96 carats. It is by any standard a collectors size stone. It is completely flawless with a standard 10x loupe. Under the microscope, while there are artifacts to be observed, it is a relatively clean stone microscopically though not flawless.
This study was a bit more difficult as I was using a better video card that actually hindered things in some instances as compared to the last one. Some artifacts you can’t detect so readily simply because they are as colorless as the body.
I initially described this stone as being D ? in color meaning a split between D and E if you compared it to a diamond. Having seen an E colored diamond, this stone has less color than that. It will disappear in a glass of water. So if you’re looking for a diamond substitute or just want something not so common and a complete freak of nature on so many levels, this is a stone you might want to acquire as part of your collection or to mount in a piece of jewelry.
Keep in mind that larger sized stones are more difficult to examine with a microscope as the one being used here, and these things have a very high dispersion. To put it in perspective to the mineral and gemology buffs who might be reading this, with the right lighting and camera angle, it looks like a colorless sphene. However, there is no such thing that I know of, but for descriptive purposes, it can appear that way.
It is also interesting to note that there is one small difference between danburites and sphenes (also known as titanite geologically). Had the conditions been a bit different and the absence of boron, this could have easily turned into a sphene as the same chemical elements are there. Danburites are like sphenes in that they have a higher disperson than a diamond, and there are very few stones that can say that. The presence of rutile inclusions has been observed in both specimens.
This is the stone face up under 15x. We can see the silver tone. Like with the first specimen, there is a very mirror like tone from the pavilion with the cotton backing. This may appear more blue due to the presence of either phosphors or a krypton/xenon blend of gases in the LED.
This is about 17x. We can begin to see some very small solid phased inclusions from this level of magnification.
This is under 24x. We can see some rutile like fields here. These aren’t smudges as this was polished with the same clean jewelers cloth that a particular vendor of diamonds sells.
This is the same view as above. However, if you notice, there is this obvious rhombohedral shaped inclusion that is solid and single phase. We see no evidence of growth rings at all. However, this inclusion and others like it suggest some metamorphic event. That will be explored in greater depth at a later time.
This is at about 30x, and is only 1 quadrant of the stone. That should give you an idea as to how large this stone is.
Take note of 2 things in a highlighted version of this image as above:
The rectangular area outlines what appears to be a possible rhombohedral/prismatic and colorless solid. Near that, we see something fuzzy that is hexagonal in shape within the same vicinity. It looks like a gas type inclusion, but my suspiscion is that this is merely artifact based on other imagery to be illustrated later in this text.
This is the same 30x view, and the stone was simply repositioned to an adjacent quadrant. We can see the rutile, and we can see what appears to be a colorless pyramidal terminating end of a rhombohedral crystal. That would be consistent with danburite or basic silicates. However, silicate in this host is more readily seen as the previous specimen imagery illustrates.
This is an area of rutile inclusions at 50x.
These are some mica appearing inclusions that are solid and single phase at 220x. Based on this, it is suggestive of some form of hydrothermal formation. That is not the same as a stone that has been produced using hydrothermal synthesis. This is suggestive of a geological occurrence, and a clue as to the supposed origin.
This is the stone at 25x with exposure to UV-A.
This is the same as the above except with UV-A off. We can observe a slight green and mostly inert fluorescence at best here and there. Some of that may or may not be artifact, but there are no signs of growth rings.
The yellow elliptical shape is there to highlight what appears to be at this view a gas inclusion. However, that’s not the case. It is not a nuance, but a legitimate artifact within the host.
This appeared to be a gas inclusion from the pavilion, however we can see a cluster of close in proximity. Aside from some faint rutile inclusions, this is observed at 61x. These are merely closely knit solids, and due to lighting conditions and the diffusion of light from them, they can appear to be gas like as one might see in other gemstones from other localities.
The same tests were done with the pavilion view with UV-A at 22x.
This is with UV-A on.
This is with UV-A off. We can see an inert green, and some indications of solid artifacts that appear to be in tact.
From the pavilion view at 40x, we can see solid inclusions that are in a more or less laminar pattern. That would be consistent with what is perhaps the c-axis of the crystal before it was cut, and consistent with the growth patterns of danburites.
Amongst other imagery, this may be more for aesthetics than any other value, but attempts were made to capture the dispersion of the stone and certain patterns projected onto the paper background that this specimen was placed over.
Note the patterns of the shadows overlapping, and note the dispersion from the stone. There are 4 LED light sources within the microscope head. Though a bit out of focus, you can observe a great deal of dispersion of light and some rainbow like gradients displaying on a plain white sheet of paper.
This is an alternate view of the same image above.
The formal study will comprise artifacts of both specimens, and further evidence and explanations will be presented there.
-joe
