| Quartz |
Quartz is the most abundant and most common mineral on the Earth. It is found in almost every geological environment and also it is at least a component of almost every rock type. It has a hexagonal crystal structure and is made of trigonal crystallized silica. It is most varied in terms of varieties, colors and forms.
The most important distinction between the types of quartz is that one is of macrocrystalline, which is individual crystal visible to the unaided eye, and the other is microcrystalline or cryptodrystalline varieties, aggregates of crysstals visible only under high magnification. Chalcedony is the generic term for cryptocrystalline quartz. The transparent variety tends to be macrocrystalline and the cryptocrystalline varieties are either translucent or mostly opaque.
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The name "quartz" has been derived from the German "Quarz," a Slavic origin. It is the most common material identified as mystical substance maban in the Australian Aboriginal mythology. Pliny the Elder, a Roman naturalist believed quartz to be a permanently frozen ice. According to him, quartz is found near glaciers in the Alps and that the crystals of quartz were fashioned into spheres to cool the hands. It was also known to him the ability of quartz to split light into a spectrum.
Nicolas Steno's study of quartz made way for the modern crystallography. His discovery states that no matter how distorted a quartz crystal is, the long prism faces always made a perfect 60 degree angle. |
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Physical Properties of Quartz |
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| Color |
Clear (in pure form) |
| Crystal habit |
6-sided prism ending in 6-sided pyramid (typical) |
| Crystal system |
Trigonal |
| Cleavage |
None |
| Fracture |
Conchoidal |
| Mohs scale hardness |
7 - lower in impure varieties |
| Luster |
Vitreous |
| Refractive index |
1.544-1.553 - Dr +0.009 (B-G interval) |
| Streak |
White |
| Specific gravity |
2.65 constant; variable in impure varieties |
| Melting point |
1650 (±75) °C |
| Boiling point |
2230 °C |
| Solubility |
H2O insoluble |
Molecular Weight of Quartz
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| Silicon |
46.74% (Si) |
100.00% (SiO2) |
| Oxygen |
53.26% (O) |
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100.00% |
100.00% = Total Oxide |
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Uses of Quartz |
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Silica for glass
Electrical components
Optical lenses
Abrasives
Gemstones
Ornamental stone
Building stone
Piezoelectricity - It creates electricity through a process known as piezoelectricity with mechanical stress given on it. Earlier, quartz crystal was uses as phonograph pickup. Now, it is used as a crystal oscillator. These oscillators are simply known as "quartzes."
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