Irtyshite is an extremely rare tantalum-titanium mineral originally discovered in the Altai Mountains. It typically occurs as small, transparent tabular crystals associated with pegmatite minerals like albite and muscovite. Due to its extreme rarity, it is almost exclusively held by advanced scientific collections or specialized mineral enthusiasts.
Is this irtyshite?
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 irtyshite with a known reference. Irtyshite sits at Mohs 7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: microscopic crystals.
Often confused with
Irtyshite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside irtyshite
Minerals reported to co-occur with irtyshite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂Ta₄O₁₁
- Mohs hardness
- 7
- Density
- 7.03 g/cm³
- Colors
- Streak
- White
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Microscopic crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As veinlets in altered thoreaulite, and inclusions in ixiolite and lithiotantite, in granite pegmatites
Where rockhounds find irtyshite
Classic worldwide localities
- Ungursai tantalum deposit, Kalba Mountains, near the Irtysh River, eastern Kazakhstan
Field-hunting tip
Where it forms: As veinlets in altered thoreaulite, and inclusions in ixiolite and lithiotantite, in granite pegmatites. If you start seeing thoreaulite, ixiolite, lithiotantite in float, you are in the right ground. Typical habit: microscopic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify irtyshite?+
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What rocks look like irtyshite?+
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Find irtyshite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
