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Optical mineralogy is the study of minerals and rocks by measuring their optical properties. Most commonly, rock and mineral samples are prepared as thin sections or grain mounts for study in the laboratory with a petrographic microscope. Optical mineralogy is used to identify the mineralogical composition of geological materials in order to ...
[3] [4] [5] The color in reflected plane polarised light is white, with very dark red internal reflections [3] and very weak pleochroism in air, fair in oil. [3] [4] Reflectivity in air at 540 nm is about 30%. It is not fluorescent. [3] Pearceite is a brittle mineral that breaks with a conchoidal to irregular fracture.
Loparite-(Ce) is a granular, brittle oxide mineral of the perovskite class. It is black to dark grey and may appear grey to white in reflected light on polished thin section with reddish brown internal reflections. [5] It has the chemical formula of (Ce,Na,Ca)(Ti,Nb)O 3. [4] Nioboloparite is a variation of loparite-(Ce) containing niobium. [6]
Such minerals are composed of parallel fibers (or contain fibrous voids or inclusions), which reflect light into a direction perpendicular to their orientation, thus forming narrow bands of light. The most famous examples are tiger's eye and cymophane, but the effect may also occur in other minerals such as aquamarine, moonstone and tourmaline.
The extremely high color saturation of bezsmertnovite is determined to be the highest of all known ore minerals. [10]: 113 In reflected light, bezsmertnovite is similar to gold, due to which it is easily detected among aggregates of bilibinskite, bogdanovite and other minerals of the group: it is the lightest of them, has a rich orange-yellow ...
The measured optical properties of Aleutite were found through reflected light. The mineral had high values of refractive indices which is typical of arsenates and vanadates. Reflectance measurements were made using a SiC standard in air which ranged from 400–700 nm.
Identification; Color: Light gray in reflected light with rose tint: ... Carlsbergite is a nitride mineral that has the chemical formula CrN, [2] or chromium nitride.
Identification; Color: ... Distinctly anisotropic in reflected light: ... also spelled löllingite, is an iron arsenide mineral with formula FeAs 2.