Siderite
Fe(CO3)IMA symbol: Sdapproved
Siderite is a carbonate or nitrate mineral with the formula Fe(CO3), crystallizing in the trigonal system. It has a Mohs hardness of 3.5-4, typically white, brown, gray or green in color, with a pearly or vitreous luster, a specific gravity of 3.83-3.88. Its streak is white.
Photos
Crystallography
| Crystal system | trigonal crystal systemWikidata (CC0) |
|---|---|
| Space group | R -3 c :H |
| Cell (Å, °) | a = 4.519, b = 4.519, c = 13.47; α = 90, β = 90, γ = 120 |
| Cell volume | 238.223 ų, Z = 6 |
| Axial ratios | 1.0000:1:2.9807calculated from COD 9015167 |
| Source structure | COD 9015167 (Physical Review B, 2010) — 1 of 38 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 2.553 | 3.384 | 1.593 | 2.26 | 1.879 | 2.018 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 43.6 | 30.8 | 25 | 23.3 | 19.2 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9015167; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 4.845 g/cm³calculated from COD 9015167 |
|---|---|
| Hardness (Mohs) | 4single sourceWikidata (CC0) 3.5-4single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.83-3.88 g/cm3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Color | brown, gray, green, red, white, yellowsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) |
| Luster | pearly, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 115.85 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Fe 48.2%, C 10.37%, O 41.43% |
Classification
| Nickel-Strunz (10th) | 5.AB.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 5.AB.05Wikidata (CC0) |