Grunerite
܆Fe2+2Fe2+5Si8O22(OH)2IMA symbol: Gruredefined
Grunerite is a silicate mineral with the formula ܆Fe2+2Fe2+5Si8O22(OH)2, crystallizing in the monoclinic system. It has typically brown, red or yellow in color, with a silky luster, a specific gravity of 3.09.
Photos
_(GeoDIL_number_-_1779).jpg){kind=link}
Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | C 1 2/m 1 |
| Cell (Å, °) | a = 9.5642, b = 18.393, c = 5.3388; α = 90, β = 101.892, γ = 90 |
| Cell volume | 919.015 ų, Z = 2 |
| Axial ratios | 0.5200:1:0.2903calculated from COD 9000000 |
| Source structure | COD 9000000 (Mineralogical Society of America Special Paper, 1969) |
Powder X-ray diffraction (calculated)
| d (Å) | 8.341 | 2.769 | 3.076 | 2.512 | 2.644 | 2.206 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 53.3 | 45.1 | 35.6 | 31.7 | 28.4 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9000000; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.515 g/cm³calculated from COD 9000000 |
|---|---|
| Specific gravity | 3.09 g/cm3single sourceFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
| Color | brown, red, yellowsingle sourceFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
| Luster | silkyFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
Classification
| Nickel-Strunz (10th) | 9.DE.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.DE.05Wikidata (CC0) |