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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 ...
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 ...
Optical properties of common minerals Name Crystal system Indicatrix Optical sign Birefringence Color in plain polars Anorthite: Triclinic: Biaxial (-) 0.013
Print/export Download as PDF; Printable version; ... Pages in category "Metaphysical properties" The following 65 pages are in this category, out of 65 total.
Quartzite can have a grainy, glassy, sandpaper-like surface. Quartzite is a hard, non-foliated metamorphic rock which was originally pure quartz sandstone. [1] [2] Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts.
Thermoluminescence from heating chlorophane specimens on a hotplate. Triboluminescence from rubbing together two quartz crystals.. First, it will be useful to introduce some mineralogical terminology for gemstones that can glow when exposed to light, friction, or heat.
High quality quartz crystals are single-crystal silica with optical or electronic properties that make them suitable for hardstone carvings. The Hindu temples in South India use this semi-precious mineral for making Shiva Lingams. Sphatikam beads are made from translucent rose quartz are cut and polished as beads.
In particular, there are crystals that have trigonal symmetry but belong to the hexagonal lattice (such as α-quartz). The hexagonal crystal family consists of the 12 point groups such that at least one of their space groups has the hexagonal lattice as underlying lattice, and is the union of the hexagonal crystal system and the trigonal ...