Tumchaite is an extremely rare silicate mineral discovered in the alkaline pegmatites of the Tumcha complex in Russia. It typically occurs as small, clear, tabular crystals associated with other rare zirconium minerals in agpaitic rock environments.
Is this tumchaite?
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 tumchaite with a known reference. Tumchaite sits at Mohs 5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Tumchaite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Tumchaite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, pale yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, aggregates.
Often confused with
Tumchaite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside tumchaite
Minerals reported to co-occur with tumchaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂ZrSi₆O₁₅·2H₂O
- Mohs hardness
- 5
- Density
- 2.42 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Aggregates
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find tumchaite
Classic worldwide localities
- Tumcha complex, Kola Peninsula, Russia
Field-hunting tip
Look in alkaline pegmatites country — that is the host setting where tumchaite typically forms. If you start seeing aegirine, arfvedsonite, microcline in float, you are in the right ground. Field specimens usually show a tabular crystals, aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find tumchaite on the map
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