Pseudobrookite
(Fe3+2Ti)O5IMA symbol: Pbrkredefined
Pseudobrookite is an oxide or hydroxide mineral with the formula (Fe3+2Ti)O5, crystallizing in the orthorhombic system. It has a Mohs hardness of 6-6.5, typically black, brown or gray in color, with a metallic or submetallic luster, a specific gravity of 4.4-4.98. Its streak is black or brown.
Photos
Crystallography
| Crystal system | orthorhombic crystal systemWikidata (CC0) |
|---|---|
| Space group | B b m m |
| Cell (Å, °) | a = 9.7131, b = 10.019, c = 3.7363; α = 90, β = 90, γ = 90 |
| Cell volume | 363.6 ų, Z = 4 |
| Axial ratios | 0.9695:1:0.3729calculated from COD 9002011 |
| Source structure | COD 9002011 (American Mineralogist, 1999) — 1 of 15 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 3.487 | 2.752 | 1.868 | 5.01 | 4.857 | 1.546 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 64.6 | 32.7 | 31.8 | 23.1 | 19.3 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9002011; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.654 g/cm³calculated from COD 9002011 |
|---|---|
| Hardness (Mohs) | 6-6.5single sourceFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
| Specific gravity | 4.4-4.98 g/cm3Ford, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
| Color | black, brown, graysingle sourceFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
| Streak | brownsingle sourceWikidata (CC0) black, brown, graysingle sourceFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
| Luster | metallic, submetallicsingle sourceFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
Classification
| Nickel-Strunz (10th) | 4.CB.15Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 4.CB.15Wikidata (CC0) |