Pseudobrookite is a titanium-iron oxide that typically occurs as small, dark, tabular or acicular crystals within cavities of volcanic rocks. It is most easily identified by its distinctive adamantine luster and its association with high-temperature minerals in igneous volcanic environments.
Is this pseudobrookite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch pseudobrookite with a known reference. Pseudobrookite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Pseudobrookite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Pseudobrookite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: dark brown, black.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular to prismatic crystals, often as thin plates or needles.
Often confused with
Pseudobrookite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Pseudobrookite leaves white, Iron Ore leaves reddish-brown to black; luster reads adamantine on Pseudobrookite and metallic to submetallic on Iron Ore.
How to tell apart: Streak differs — Pseudobrookite leaves white, Manaccanite leaves black; luster reads adamantine on Pseudobrookite and submetallic on Manaccanite.
How to tell apart: Streak differs — Pseudobrookite leaves white, Brookite leaves white to yellowish-white; luster reads adamantine on Pseudobrookite and submetallic on Brookite.
Often found alongside pseudobrookite
Minerals reported to co-occur with pseudobrookite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₂TiO₅
- Mohs hardness
- 6
- Density
- 4.3-4.4 g/cm³
- Colors
- Streak
- White
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular to Prismatic Crystals, Often as Thin Plates or Needles
- Cleavage
- Distinct On {010}
- Rarity
- Uncommon
- Uses
- Collector, Scientific Research
- Host rock
- Volcanic Rocks Such as Basalt and Rhyolite, Often in Gas Cavities
- Typical price
- $20-150 for micro to thumbnail specimens
Where rockhounds find pseudobrookite
Classic worldwide localities
- Eifel Mountains, Germany
- Auvergne, France
- Durango, Mexico
- Utah, USA
- Italy
Field-hunting tip
Look in volcanic rocks such as basalt and rhyolite, often in gas cavities country — that is the host setting where pseudobrookite typically forms. If you start seeing sanidine, magnetite, fayalite in float, you are in the right ground. Field specimens usually show a tabular to prismatic crystals, often as thin plates or needles habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find pseudobrookite on the map
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