Optical Properties Of Minerals In Thin Section

Optical mineralogy is the study of minerals and rocks by measuring their optical properties.

Optical properties of minerals in thin section. As different minerals have different optical properties most rock forming minerals can be easily identified. Calcite thin section photomicrographs are taken in plane polarized light and cross polarized light and can easily be recognized under the microscope. Ppl passes through the 30μm thickness of the thin section.

The electromagnetic light waves interact with the electrons in the minerals and slow down the higher the density of electrons the slower the light wave travels. With colorless minerals in thin section e g. Most commonly rock and mineral samples are prepared as thin sections or grain mounts for study in the laboratory with a petrographic microscope.

Refractive index birefringence michel lévy interference. 40x to view this mineral in crossed polars click here. High 17 40 ve extreme pinky buff colours occasional.

Common opaque minerals are graphite oxides such as magnetite or ilmenite and sulfides such as pyrite. Titanite im colourless or pale brown. Quartz white light passes unaffected through the mineral and none of its wavelengths is absorbed whereas with opaque minerals such as metallic ores all wavelengths are absorbed and the minerals appear black.

Optical mineralogy is used to identify the mineralogical composition of geological materials in order to help reveal their origin and evolution. When placed between two polarizing filters set at right angles to each other the optical properties of the minerals in the thin section alter the colour and intensity of the light as seen by the viewer. Orthoclase potassium feldspar or k spar in plane polarized light.

Appear black in both pp and xp light at all times. Thin section plane polars thin section crossed polars. Https youtu be w orthoclase xpl orthoclase crossed.