Ilvaite
CaFe3+Fe2+2O(Si2O7)(OH)IMA symbol: Ilvgrandfathered
Ilvaite is a silicate mineral with the formula CaFe3+Fe2+2O(Si2O7)(OH), crystallizing in the orthorhombic system. It has a Mohs hardness of 5.5-6, typically black or gray in color, with a metallic or submetallic luster, a specific gravity of 3.99-4.05. Its streak is black or brown.
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Crystallography
| Crystal system | orthorhombic crystal systemWikidata (CC0) |
|---|---|
| Space group | P n a m |
| Cell (Å, °) | a = 13.014, b = 8.867, c = 5.838; α = 90, β = 90, γ = 90 |
| Cell volume | 673.677 ų, Z = 4 |
| Axial ratios | 1.4677:1:0.6584calculated from COD 9002759 |
| Source structure | COD 9002759 (American Mineralogist, 2002) — 1 of 39 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 2.712 | 2.842 | 7.328 | 2.691 | 2.11 | 1.476 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 94.1 | 91.1 | 70.3 | 53.1 | 51.9 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9002759; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 4.027 g/cm³calculated from COD 9002759 |
|---|---|
| Hardness (Mohs) | 5.5-6single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.99-4.05 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, graysingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | blacksingle sourceWikidata (CC0) black, brown, greensingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | metallic, submetallicsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Classification
| Nickel-Strunz (10th) | 9.BE.07Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.BE.07Wikidata (CC0) |
| Dana (8th) | 56.2.3.3Wikidata (CC0) |