Usturite is a rare, radioactive mineral belonging to the zirconolite group, typically found in alkaline igneous rocks. It is identified by its dark, often bipyramidal crystal habits and submetallic luster. Due to its radioactive nature, collectors should store it appropriately and minimize physical contact.
Is this usturite?
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 usturite with a known reference. Usturite sits at Mohs 5-6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Usturite leaves a brown streak.
- 3Read the lusterHold the specimen under a strong light. Usturite typically shows a submetallic luster.
- 4Match the color rangeCompare against the expected color range: dark brown, black.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: bipyramidal crystals.
Often confused with
Usturite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Zircon is the harder of the two (Mohs 7.5 vs. 5-6); streak differs — Usturite leaves brown, Zircon leaves white; luster reads submetallic on Usturite and adamantine on Zircon.
How to tell apart: Streak differs — Usturite leaves brown, Euxenite leaves yellowish, grayish, or reddish-brown; luster reads submetallic on Usturite and submetallic, resinous, greasy on Euxenite.
Often found alongside usturite
Minerals reported to co-occur with usturite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Zr(Ti,Fe,Nb,Ta)₂(O,OH)₈
- Mohs hardness
- 5-6
- Density
- 4.15 g/cm³
- Colors
- Streak
- Brown
- Luster
- Submetallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Bipyramidal Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find usturite
Classic worldwide localities
- Ilmen Mountains, Russia
- Kola Peninsula, Russia
Field-hunting tip
Look in alkaline pegmatites country — that is the host setting where usturite typically forms. If you start seeing zircon, feldspar, mica in float, you are in the right ground. Field specimens usually show a bipyramidal crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find usturite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
