| Pseudobrookite | |
| Category: | Oxide mineral |
| Formula: | Fe2TiO5 |
| Imasymbol: | Pbrk[1] |
| Strunz: | 4.CB.15 |
| System: | Orthorhombic |
| Class: | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
| Symmetry: | Bbmm |
| Unit Cell: | a = 9.81 Å, b = 9.95 Å, c = 3.73 Å; Z = 8 |
| Color: | Dark reddish brown, brownish black, black |
| Habit: | Prismatic to needle like, striated |
| Cleavage: | Distinct on |
| Fracture: | Uneven to subconchoidal |
| Mohs: | 6 |
| Luster: | Adamantine, greasy, metallic |
| Streak: | Brown |
| Diaphaneity: | Opaque, transparent in thin splinters |
| Gravity: | 4.33–4.39 |
| Opticalprop: | Biaxial (+) |
| Refractive: | nα = 2.350 nβ = 2.390 nγ = 2.420 |
| Birefringence: | δ = 0.070 |
| 2V: | Measured: 50° |
| References: | [2] [3] [4] |
Pseudobrookite is an iron titanium oxide mineral with formula: Fe2TiO5[2] or (Fe3+,Fe2+)2(2+)O5.[3]
Pseudobrookite was first described in 1878 for an occurrence in Uroi Hill (Arany Hill), Simeria, Hunedoara County, Romania. The name is from Greek ψευδής, for false, and brookite because of its misleading similar appearance to brookite.[2]
Pseudobrookite forms as pneumatolytic deposition and alteration within titanium-rich volcanic rocks such as andesite, rhyolite or basalt. It may be associated with xenoliths contained in the volcanics. It also commonly occurs in lithophysae.[4]
It occurs associated with hematite, magnetite, bixbyite, ilmenite, enstatite-ferrosilite, tridymite, quartz, sanidine, topaz, spessartine, beryl, mica, cassiterite and apatite.[4]
Occurrences include:[4]