Usturite is a rare calcium antimony zirconium oxide, typically light brown or yellow. It was approved as a distinct mineral species in 2009. It was first described from Within the Upper Chegem caldera, Northern Caucasus, Kabardino-Balkaria, Russia.
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 white with yellow tint streak.
- 3Read the lusterHold the specimen under a strong light. Usturite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: light brown, yellow.
- 5Look at form & habitCrystal system: cubic. 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, so Usturite leaves white with yellow tint, Zircon leaves white; luster reads vitreous on Usturite and adamantine on Zircon.
How to tell apart: Streak differs, so Usturite leaves white with yellow tint, Euxenite-(Y) leaves yellowish-brown; luster reads vitreous on Usturite and submetallic on Euxenite-(Y).
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
- Ca₃(SbZr)(FeO₄)₃
- Mohs hardness
- 5-6
- Density
- 4.470 g/cm³
- Colors
- Streak
- White with Yellow Tint
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Bipyramidal Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Pegmatites
Where rockhounds find usturite
Classic worldwide localities
- Ilmen Mountains, Russia
- Kola Peninsula, Russia
Field-hunting tip
Look in alkaline pegmatites country, 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
How do you identify usturite?+
Where is usturite found?+
Is usturite safe to handle?+
What rocks look like usturite?+
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Find usturite on the map
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