last modified: Tuesday, 26-May-2009 03:45:50 CEST
Table of Mineral Data
|
Mineralogical Classification | |
|---|---|
| According to Dana | 75.1.3.1: Tectosilicates - Si Tetrahedral Frameworks |
| According to Strunz | 4/D.01-10: Oxides Oxides with metal to oxygen ratio of 1:2 - Quartz Group |
| According to Hey's Chemical Index of Minerals |
7.8.1 Oxides |
|
Crystallographic Data | |
| Crystal System | Hexagonal / Trigonal |
| Crystal Class Hermann Mauguin Symbols |
Trigonal Trapezohedral
3 2 |
| Space Group | P3121 (left hand), P3221 (right hand) |
| Unit Cell Data | a = 4.9133, c = 5.4053 Ratio a:c = 1:1.10013 Z=3 |
|
Optical Properties | |
| Color | colorless if pure, otherwise any color |
| Streak | none / white if pure |
| Luster | vitreous Cryptocrystalline: waxy to dull, vitreous if polished |
| Diapheny | transparent if pure, otherwise transparent to opaque |
| Fluorescence | none |
| Refractive Indices for Na D-Line (589nm) |
no=1.54422 ne=1.55332 Dispersion=0.0091 Cryptocrystalline: n = 1.53-1.54 |
| Birefringence | uniaxial positive: ne-no = +0.00910 lower in cryptocrystalline quartz |
| Pleochroism / Dichroism | none if pure, weak dichroism is observed in smoky quartz, amethyst, and certain citrines |
| Optical Activity [γ]= degrees / mm |
γ = 21.73° for Na D-Line (589nm) |
|
Electrical Properties | |
| Relative Permittivity | Dielectric Number εr: 4.69 parallel to a-axis εr: 5.06 parallel to c-axis |
| Behavior in Magnetic Fields | diamagnetic |
|
Mechanical Properties | |
| Fracture | conchoidal, sometimes uneven |
| Cleavage | weak tendency to break along rhombohedral and prism planes |
| Tenacity | brittle |
| Modulus of Elasticity | |
| Mohs Hardness | Macrocrystalline: 7 Cryptocrystalline: 6.5-7 |
| Vicker's Indentation Hardness | Macrocrystalline: average 1182 kg/mm2 (basal plane 1103 kg/mm2, prism faces 1260 kg/mm2) |
| Rosival Grinding Hardness | Macrocrystalline: 100 (quartz is the reference) |
| Specific Weight | 2.6481 g/cm3 |
| Melting Point | 1705°C |
| Boiling Point | 2477°C |
| Thermal Expansion Coefficient | |
| Thermal Conductivity [λ] = W/m×K |
λ = 12.14 parallel to c-axis λ = 6.70 parallel to a-axis |
Further Information, Literature, Links
A table of quartz properties can be found at mindat.org:http://www.mindat.org/min-3337.html
Another table at www.webmineral.com:
http://www.webmineral.com/data/Quartz.shtml
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