Quartz
SiO2IMA symbol: Qzapproved
Quartz is an oxide or hydroxide mineral with the formula SiO2, crystallizing in the trigonal system. It has a Mohs hardness of 7, typically colorless, black, blue or brown in color, with a dull or greasy luster, a specific gravity of 2.6-2.64. Its streak is white.
Photos
Crystallography
| Crystal system | trigonal crystal systemWikidata (CC0) |
|---|---|
| Space group | P 32 2 1 |
| Cell (Å, °) | a = 4.91239, b = 4.91239, c = 5.40385; α = 90, β = 90, γ = 120 |
| Cell volume | 112.9 ų, Z = 3 |
| Axial ratios | 1.0000:1:1.1000calculated from COD 5000035 |
| Source structure | COD 5000035 (Journal of Applied Crystallography, 1988) — 1 of 49 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 3.343 | 4.254 | 1.817 | 1.541 | 1.375 | 2.281 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 19.8 | 13.5 | 10.1 | 7.8 | 7.4 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 5000035; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 2.65 g/cm³calculated from COD 5000035 |
|---|---|
| Hardness (Mohs) | 7single sourceWikidata (CC0) 7single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 2.6-2.64 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, blue, brown, colorless, green, red, yellowsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | blacksingle sourceWikidata (CC0) whitesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | dull, greasy, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 60.08 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Si 46.74%, O 53.26% |
Classification
| Nickel-Strunz (10th) | 4.DA.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 4.DA.05Wikidata (CC0) |
| Dana (8th) | 75.1.3.1Wikidata (CC0) |