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Riebeckite is a sodium-rich member of the amphibole group of silicate minerals, chemical formula Na 2 (Fe 2+ 3 Fe 3+ 2)Si 8 O 22 (OH) 2.It forms a solid solution series with magnesioriebeckite.
Rutilated quartz used as a gemstone. Rutilated quartz is a variety of quartz which contains acicular (needle-like) inclusions of rutile. [1] It is used for gemstones. These inclusions mostly look golden, but they also can appear silver, copper red or black.
Quartz is, therefore, classified structurally as a framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. [10] Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation ...
The stars are caused by the light reflecting from needle-like inclusions of rutile aligned perpendicularly to the rays of the star. The star-effect may be also caused by the inclusions of hematite. In black star sapphire hematite needles formed parallel to the faces of the second order prism produce asterism.
The UV absorption of nano-sized rutile particles is blue-shifted compared to bulk rutile so that higher-energy UV light is absorbed by the nanoparticles. Hence, they are used in sunscreens to protect against UV-induced skin damage. Small rutile needles present in gems are responsible for an optical phenomenon known as asterism. Asteriated gems ...
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Main chrysoberyl producing countries. The mineral or gemstone chrysoberyl is an aluminate of beryllium with the formula Be Al 2 O 4. [5] [6] The name chrysoberyl is derived from the Greek words χρυσός chrysos and βήρυλλος beryllos, meaning "a gold-white spar".
Boudinaged quartz vein (with strain fringe) showing sinistral shear sense. Starlight Pit, Fortnum Gold Mine, Western Australia. Veins are common features in rocks and are evidence of fluid flow in fracture systems. [7] Veins provide information on stress, strain, pressure, temperature, fluid origin and fluid composition during their formation. [3]