Transmitted Light / Lumière Transmise
Relief
Thin section 2162-6, PPL, 50x magnification, 360 degree rotation. Notice the low relief of quartz (centerered in the crosshair) that is surrounded by the higher relief of barite.
Thin section 2162-23, PPL, 10x magnification, 360 degree rotation. Calcite grain (grey-white) showing a change of relief. Minimum relief can be seen at the its starting position and after a ~180 degree rotation whereas its maximum relief can be seen after a ~90 degree and ~270 degree rotation.
Pleochroism / Pléochroïsme
Thin section 2162-2, PPL, 10x mangification, 360 degree rotation. Aegirine displaying a pale green to forest green pleochroism.
Thin section 2162-2, PPL, 10x magnification, 360 degree rotation. Biotite displaying an orange-brown to dark brown pleochroism.
Birefringence
Thin section 2162-6, XPL, 5x magnification, 360 degree rotation. Quartz and barite displaying low birefringence colours (grey to yellow 1st order).
Thin section 2162-5, XPL, 5x magnification, 360 degree rotation. Olivine displaying medium birefringence colours (blue 2nd order).
Thin section 2162-35, XPL, 10x magnification, 360 degree rotation. Cluster of muscovite displaying high birefringence colours (various colours of the 3rd order). Notice how interference colours become more and more ''washed'' as the order increases.
Thin section 2162-7, XPL, 5x magnification, 360 degree rotation. Calcite displaying extreme birefrigence colours (up to the 8th order!).
Extinction
Thin section 2162-18, PPL/XPL, 5x magnification, 180 degree rotation. Amphibole displaying parallel extinction to its long axis.
Thin section 2162-22, PPL/XPL, 10x magnification, 180 degree rotation. Sillimanite displaying parallel extinction to its long axis.
Thin section 2162-6, XPL, 5x magnification, 180 degree rotation. Barite displaying parallel extinction to its clavage planes.
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Thin section 2162-31, XPL, 5x magnification, 180 degree rotation. Plagioclase displaying inclined extinction to its polysynthetic twinning.
Reflected Light / Lumière Réfléchie
Reflectance
Thin section 2162-43, reflected light. Notice the much higher reflectance of pyrite (yellow-white colour) compared to chromite (grey), which in turn is more reflective than the surrounding gangue (grey-black, serpentine).
Thin section 2162-48, reflected light. Notice the higher reflectance of pentlandite (white cream colour) compared to magnetite (grey). Both pyrrhotite (pinkish-beige) and chalcopyrite (yellow) have intermediate reflectance values between pentlandite and magnetite.
Bireflectance
Thin section 2162-47, reflected light, 5x magnification, 360 degree rotation. Ilmenite with hematite exsolutions displaying a pinkish-brown to darker brown bireflectance.
Thin section 2162-48, reflected light, 10x magnification, 360 degree rotation. Pyrrhotite displaying a pinkish-beige to reddish brown bireflectance.
Scratch hardness / Dureté au polissage
Thin section 2162-44, reflected light. Notice the higher abundance of scratches on the surface of galena (white) compared to the surface of sphalerite (grey).
Thin section 2162-48, reflected light. Notice how the scratch in the middle of the picture appears on the surface of pyrrhotite (pinkish-beige) and pentlandite (white cream colour) but does not appear on the surface of magnetite (grey).