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Lustre (British English) or luster (American English; see spelling differences) is the way light interacts with the surface of a crystal, rock, or mineral. The word traces its origins back to the Latin lux , meaning "light", and generally implies radiance, gloss, or brilliance.
Is the mineral reactive or nonreactive when exposed to other compounds? For example, minerals with calcium carbonate composition typically fizz when exposed to a weak acid. Associated rock type; With what rock type and/or other minerals is this mineral found? Degree of metamorphism and alteration; Mineral shape, properties or form been altered.
Barrerite is a tectosilicate mineral and a member of the zeolite family. It is one of the rarer zeolites. It was named for Richard Barrer, a New Zealand-born chemist. [4] Barrerite crystal are white to pinkish, with a vitreous-glassy luster. The crystal system is orthorhombic and is flat and tabular in appearance. It has a Mohs hardness of 3 to ...
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 ...
The transparent or translucent mineraloid has a globular structure, a vitreous luster, and a white streak. Hyalite is an amorphous form of silica (SiO 2) formed as a volcanic sublimate in volcanic or pegmatic rock and is thereby considered a mineraloid. It contains 3–8% water, either as a silanol group or in molecular form.
It is generally glassy or fine-grained in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent of granite.
Micas are translucent to opaque with a distinct vitreous or pearly luster, and different mica minerals display colors ranging from white to green or red to black. Deposits of mica tend to have a flaky or platy appearance.
Under the microscope the spherulites are of circular outline and are composed of thin divergent fibers that are crystalline as verified with polarized light. Between crossed Nicols, a black cross appears in the spherulite; its axes are usually perpendicular to one another and parallel to the crosshairs; as the microscope stage is rotated the cross remains steady; between the black arms there ...