What are the 4 optical properties of minerals?
Optical Properties of Minerals: Luster, Light Transmission, Color & Streak.
What is the Michel Levy chart used for?
Thus, the Michel-Lévy Birefringence Chart enables the microscopist to rapidly determine thickness, birefringence, or retardation, knowing the other two quantities. The original chart was used for aiding in the identification of minerals that make up rocks.
Why do we study optical mineralogy?
Optical mineralogy is the study of minerals and rocks by measuring their optical properties. Optical mineralogy is used to identify the mineralogical composition of geological materials in order to help reveal their origin and evolution.
What is refractive index in optical mineralogy?
The refractive index a mineral exhibits is more directly to the vibration direction than to the ray path. The observable refractive index is parallel to the vibration direction for special directions in anisotropic and all directions in isotropic crystals it is perpendicular to the ray path.
What are optical properties of mineral?
These three attributes (reflection, absorption, and passing through) determine the color and transparency of a substance. Optical properties relevant to minerals and gems: Refractive Index (RI) Double Refraction (DR)
How does the Michel Levy chart help determine the birefringence?
The Michel-Levy chart is utilized by comparing the highest-order interference colors displayed by the specimen in the microscope to those contained on the chart.
What causes birefringence?
Modified proteins such as immunoglobulin light chains abnormally accumulate between cells, forming fibrils. Multiple folds of these fibers line up and take on a beta-pleated sheet conformation. Congo red dye intercalates between the folds and, when observed under polarized light, causes birefringence.
What is mineralogy and petrology?
Petrology is the study of rocks – igneous, metamorphic, and sedimentary – and the processes that form and transform them. Mineralogy is the study of the chemistry, crystal structure and physical properties of the mineral constituents of rocks.
What is thin section analysis?
Micromorphology, or thin-section analysis, is the microscopic examination of the composition and structure of sediments. It was originally developed in soil science, with concepts of plasmic fabric and morphological features and structures dating from the early 1960s1.
What is interference color in optical mineralogy?
interference colours (polarization colours) In mineral optics, the colours produced when the analyser is inserted on a thin-section microscope. They are produced as a result of birefringence (double refraction) whereby one ray of light is retarded relative to the other.
What is interference Colour in optical mineralogy?
What is interference colour of a mineral? Ans. The colour perceived by us when a mineral grain is observed between cross polarizers is called Interference colour. It results due to light being split into two rays on passing through anisotropic mineral with different electronic environment, which varies with direction.