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The cryptocrystalline varieties are either translucent or mostly opaque, while the macrocrystalline varieties tend to be more transparent. Chalcedony is a cryptocrystalline form of silica consisting of fine intergrowths of both quartz, and its monoclinic polymorph moganite . [ 32 ]
After crystallization the dominant crystal phase in this type of glass-ceramic is a high-quartz solid solution (HQ s.s.). If the glass-ceramic is subjected to a more intense heat treatment, this HQ s.s. transforms into a keatite-solid solution (K s.s., sometimes wrongly named as beta-spodumene). This transition is non-reversible and ...
Chalcedony's standard chemical structure (based on the chemical structure of quartz) is SiO 2 (silicon dioxide). Chalcedony has a waxy luster, and may be semitransparent or translucent. It can assume a wide range of colors, but those most commonly seen are white to gray, grayish-blue or a shade of brown ranging from pale to nearly black.
Smoky quartz is a brownish grey, translucent variety of quartz that ranges in clarity from almost complete transparency to an almost-opaque brownish-gray or black crystals. [6] The color of smoky quartz is produced when natural radiation, emitted from the surrounding rock, activates color centers around aluminum impurities within the ...
Translucent fused-quartz tubes are commonly used to sheathe electric elements in room heaters, industrial furnaces, and other similar applications. Owing to its low mechanical damping at ordinary temperatures, it is used for high-Q resonators, in particular, for wine-glass resonator of hemispherical resonator gyro.
This type of lustre is one of the most commonly seen, [9] and occurs in transparent or translucent minerals with relatively low refractive indices. [2] Common examples include calcite , quartz , topaz , beryl , tourmaline and fluorite , among others.
Transparent armor windows must also be compatible with night vision equipment. New materials that are thinner, lightweight, and offer better ballistic performance are being sought. [54] [55] Existing transparent armor systems typically have many layers, separated by polymer (e.g. polycarbonate) interlayers. The polymer interlayer is used to ...
Quartz from Brazil with visible surface staining, sometimes incorrectly identified as citrine. Clear quartz with natural iron inclusions or limonite staining may resemble citrine. [2] However, these crystals will either have coloration only on the surface or in certain spots within the crystal. Quartz that derives its color from coatings or ...