Forsterite
Mg2(SiO4)IMA symbol: Fograndfathered
Forsterite is a silicate mineral with the formula Mg2(SiO4), crystallizing in the orthorhombic system. It has a Mohs hardness of 6-7, typically white, gray, red or yellow in color, with a vitreous luster, a specific gravity of 3.21-3.33. 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 = 4.7515, b = 10.2127, c = 5.9854; α = 90, β = 90, γ = 90 |
| Cell volume | 290.445 ų, Z = 4 |
| Axial ratios | 0.4653:1:0.5861calculated from COD 1572969 |
| Source structure | COD 1572969 (IUCrJ, 2024) — 1 of 109 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 2.458 | 2.512 | 3.885 | 1.748 | 2.767 | 2.269 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 80.2 | 68.2 | 67.8 | 63.6 | 44 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 1572969; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.217 g/cm³calculated from COD 1572969 |
|---|---|
| Hardness (Mohs) | 7single sourceWikidata (CC0) 6-7single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.21-3.33 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | gray, red, white, yellowsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) |
| Luster | vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 140.69 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Mg 34.55%, Si 19.96%, O 45.49% |
Classification
| Nickel-Strunz (10th) | 9.AC.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.AC.05Wikidata (CC0) |
| Dana (8th) | 51.3.1.2Wikidata (CC0) |