GEOLOGY

Detailed explanation-1: -Polarized light microscopy is capable of providing information on absorption color and optical path boundaries between minerals of differing refractive indices, in a manner similar to brightfield illumination, but the technique can also distinguish between isotropic and anisotropic substances.

Detailed explanation-2: -Pleochroism is when a mineral changes color as it is rotated relative to the polarizer in plane polarized light. This effectively shows how the color properties of the mineral vary with direction within the crystal structure. Testing for pleochroism using a polarizing light microscope is straightforward.

Detailed explanation-3: -Cross-polarisation, with regard to visible light, is a process wherein two polarisers with perpendicular orientation to one another are used on the incident and reflected lights. Under cross-polarised light birefringent structures which are otherwise invisible become apparent.

Detailed explanation-4: -The polarizing microscope is particularly useful in the study of birefringent materials such as crystals and strained non-crystalline substances. It is widely used for chemical microscopy and optical mineralogy. The current specimen is equipped with a quick change, centering nosepiece and a graduated, rotating stage.