Hematite
Fe2O3IMA symbol: Hemapproved
Hematite is an oxide or hydroxide mineral with the formula Fe2O3, crystallizing in the trigonal system. It has a Mohs hardness of 5.5-6.5, typically black, gray or red in color, with a metallic luster, a specific gravity of 4.9-5.5. Its streak is brown or red.
Photos
Crystallography
| Crystal system | trigonal crystal systemWikidata (CC0) |
|---|---|
| Space group | R -3 c :H |
| Cell (Å, °) | a = 5.0355, b = 5.0355, c = 13.7471; α = 90, β = 90, γ = 120 |
| Cell volume | 301.88 ų, Z = 6 |
| Axial ratios | 1.0000:1:2.7300calculated from COD 2101167 |
| Source structure | COD 2101167 (Acta Crystallographica Section B, 1994) — 1 of 13 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 2.699 | 2.518 | 1.695 | 1.841 | 1.486 | 1.454 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 74.3 | 47.5 | 38.6 | 32.9 | 32 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 2101167; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 5.27 g/cm³calculated from COD 2101167 |
|---|---|
| Hardness (Mohs) | 6single sourceWikidata (CC0) 5.5-6.5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 4.9-5.5 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, gray, redsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | brown, redsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | metallicsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 159.69 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Fe 69.94%, O 30.06% |
Classification
| Nickel-Strunz (10th) | 4.CB.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 4.CB.05Wikidata (CC0) |
| Dana (8th) | 4.3.1.2Wikidata (CC0) |