The following is a brief study using microscopic imagery regarding a pink tourmaline specimen from AJS Gems that was acquired some time ago. This was originally documented as a study of 3 tourmalines; most of which were acquired from AJS Gems. There will be a 4th study conducted in a like manner at a later time to include another specimen. A more detailed study or addendum to this might be published at a later date perhaps.
This following images depict a 4.16 carat pink tourmaline, and it was disclosed as being from Nigeria and unheated. The very strong and intense pink colors have been said to originate from Nigeria, and don’t need heating as a result. There is an absence of orange undertones, but in certain lighting conditions, you can see more or less of it. It doesn’t have the orange color shift property that a Brazilian specimen from acquired from AJS Gems as well. I found all sorts of interesting artifacts in this particular tourmaline.
These images are uncompressed and unedited with the exception of green elliptical shapes to draw your attention to certain things that I thought were of interest. Other than the interpolation for resizing with the microscope software, no revisions have been made. Note that the blue background is actually a white napkin, so the colors for some reason are off a bit. I don’t have any software to color correct things anymore since my OS upgrade-otherwise I’d illustrate both the original and color corrected versions. Unless otherwise specified, the only light source being used is the LED light source from the microscope used. No ambient light was present at the time these images were obtained; a darkroom type condition was used for the study of this particular specimen.
Under a polariscope, and 20x magnification, there is evidence of a pink to orange pleochroism without the filters crossed over the diffused light source. With the polarizing filters crossed, there is evidence of double refraction consistent with tourmalines. I could not obtain an accurate optic sign and character with my chonoscope. Then again, I suspect this is due to the scope itself as my particular one is a pain to work with. I did see some hint of yellow towards the outside perimeter of where the optic character would be, thus suggesting it’s negative. Tourmalines for the most part are uni-axial negative with some exceptions.
Additionally, when I placed the stone directly over the bottom plate, I did see a lot lighter color and one portion of some growth rings. They seemed to be more or less linear with minimal delineation before an arc. They didn’t appear to be completely curvilinear like you would find in a synthetic stone. This region was between the bottom quarter and third of the stone in which these were observed with diffused polarized light. There was evidence of pink color zoning much like you might see in a Ceylon sapphire of some color, and the zoning appeared to be consistent with some other smaller specimens I examined under a loupe under incandescent lighting. This zoning was isolated, and the stone in it’s entirety appeared to be anisotropic through and through with crossed and uncrossed polars. I wasn’t able to obtain imagery of this zoning due to limitations of ergonomic design of the equipment being used, but I have found it in another tourmaline specimen. That imagery will be published at a later date.
This was originally observed with some solid inclusions near the top left region of this image adjacent to each other at 30x that illustrate some misshapen inclusions. However, further examination of this image shows what looks like a terminal end on 2 crystals side by side. These appear to be in tact. Note the reflection off the faces of the one terminal end. These 2 are circled in green. This misshapen part could suggest thermal enhancement or some other thermal event that occurred naturally. However, the terminal ends suggest an absence of thermal enhancements.
Tags: joe blog, pink tourmaline, tourmaline
