On the attachment you can observe four distinct photos. I know that calcographic studies are not very exact and are taken over years. Because I can't do SEM-EDX or EPMA analyses at this moment I just want to explore the samples and to find some good points. I want some advice about what the minerals could be (see attachment photo ~1.9 MB):
1) In the first case, it is a sulphosalt, most probably a Burnonite - Seligmannite. But the questions is: the difference in color (some grains with grey anisotropy and other with blue color, both with parquet twins), could be two different members of that series?
2 and 3) It is isotropic? In my opinion, it is something from the Td group. I don't think it is a Tetrahedrite. Based on the color and Raman analyses the Td has a dark brown colour (with crossed nicols). For the grains from point 2 and 3) with a bluish tint I didn't do Raman analyses because they are too small to focus on with the laser.
4) A grain with an olive color and with a medium anisotropy. I haven't seen it before in other samples.
Looking forward to any suggestions
Microphotographs of polished sections are difficult to analyze, esp. when you do not use oil immersion objectives. I guess 2) and 3) are indeed fahlore (tennantite-rich fahlore is more grey with a green tint and has no brown). To 1): could also be bournonite. Different colors with crossed polars occur, when the polars are not crossed exactly 90 degree. Hope this will usefull (and not to late).
Indeed, there is Tennantite (after microprobe analyses), and for the point #1 you're right, it is bournonite-seligmanite.
Thanks for your time!
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