pseudobrookite

{{Short description|Iron titanium oxide mineral}}

{{infobox mineral

| name = Pseudobrookite

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| image = Pseudobrookite-219124.jpg

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| caption = Spray of pseudobrookite needles from Topaz Mountain in Utah (size: 2.7 × 2.0 × 1.6 cm)

| category = Oxide mineral

| formula = Fe₂TiO₅

| IMAsymbol = Pbrk{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|url=https://www.cambridge.org/core/journals/mineralogical-magazine/article/imacnmnc-approved-mineral-symbols/62311F45ED37831D78603C6E6B25EE0A|journal=Mineralogical Magazine|volume=85|issue=3 |pages=291–320|doi=10.1180/mgm.2021.43 |bibcode=2021MinM...85..291W |s2cid=235729616 |doi-access=free}}

| molweight =

| strunz = 4.CB.15

| dana =

| 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

| colour =

| habit = Prismatic to needle like, striated

| twinning =

| cleavage = Distinct on {010}

| fracture = Uneven to subconchoidal

| tenacity =

| mohs = 6

| luster = Adamantine, greasy, metallic

| streak = Brown

| diaphaneity = Opaque, transparent in thin splinters

| gravity = 4.33–4.39

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| opticalprop = Biaxial (+)

| refractive = n_α = 2.350 n_β = 2.390 n_γ = 2.420

| birefringence = δ = 0.070

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| 2V = Measured: 50°

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| references = [http://www.mindat.org/min-3302.html Pseudobrookite on Mindat.org][http://www.webmineral.com/data/Pseudobrookite.shtml Pseudobrookite on Webmin][http://rruff.geo.arizona.edu/doclib/hom/pseudobrookite.pdf Handbook of Mineralogy]

}}

Pseudobrookite is an iron titanium oxide mineral with formula: Fe₂TiO₅ or (Fe³⁺,Fe²⁺)₂({{not a typo|Ti,Fe}}²⁺)O₅.