Tengchongite is an exceptionally rare uranium-molybdenum mineral discovered in the oxidized zones of uranium deposits. It typically forms delicate orange to yellow platy crystals or crusts and is highly sought after by radioactive mineral specialists.
Is this tengchongite?
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 tengchongite with a known reference. Tengchongite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Tengchongite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Tengchongite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: orange, yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: platy crystals, crusts, aggregates.
Often confused with
Tengchongite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Tengchongite leaves yellow, Autunite leaves pale yellow.
How to tell apart: Streak differs — Tengchongite leaves yellow, Torbernite leaves pale green; luster reads pearly on Tengchongite and vitreous on Torbernite.
Often found alongside tengchongite
Minerals reported to co-occur with tengchongite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca(UO₂)₆(MoO₄)₂(OH)₁₂·12H₂O
- Mohs hardness
- 2
- Density
- 4.45 g/cm³
- Streak
- Yellow
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Platy Crystals, Crusts, Aggregates
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Uranium Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find tengchongite
Classic worldwide localities
- Tengchong, Yunnan Province, China
Field-hunting tip
Look in oxidized zones of uranium deposits country — that is the host setting where tengchongite typically forms. If you start seeing uraninite, calcite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts, aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tengchongite?+
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Find tengchongite on the map
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