Fayalite
Fe2+2(SiO4)IMA symbol: Fagrandfathered
Fayalite is a silicate mineral with the formula Fe2+2(SiO4), crystallizing in the orthorhombic system. It has a Mohs hardness of 6.5, typically black, brown or yellow in color, with a resinous luster, a specific gravity of 4-4.14. Its streak is white.
Photos
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Crystallography
| Crystal system | orthorhombic crystal systemWikidata (CC0) |
|---|---|
| Space group | P b n m |
| Cell (Å, °) | a = 4.8195, b = 10.4788, c = 6.0873; α = 90, β = 90, γ = 90 |
| Cell volume | 307.4 ų, Z = 4 |
| Axial ratios | 0.4599:1:0.5809calculated from COD 1000064 |
| Source structure | COD 1000064 (Acta Crystallographica B (24,1968-38,1982), 1981) — 1 of 30 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 2.499 | 2.828 | 1.777 | 2.565 | 3.555 | 2.632 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 93.1 | 74.5 | 64 | 60.7 | 33.9 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 1000064; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 4.403 g/cm³calculated from COD 1000064 |
|---|---|
| Hardness (Mohs) | 6.5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 4-4.14 g/cm3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, brown, yellowsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) |
| Luster | resinoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Classification
| Nickel-Strunz (10th) | 9.AC.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.AC.05Wikidata (CC0) |
| Dana (8th) | 51.3.1.1Wikidata (CC0) |