Kyawthuite is currently recognized as the rarest mineral in the world, with only a single documented specimen discovered in the Mogok Valley of Myanmar. It is a bismuth antimony oxide forming small, orange, transparent tabular crystals that show exceptional luster.
Is this kyawthuite?
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 kyawthuite with a known reference. Kyawthuite 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: orange with red overtone.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: small tabular crystals.
Often confused with
Kyawthuite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Kyawthuite is noticeably harder (Mohs 5 vs. 3); luster reads adamantine on Kyawthuite and vitreous on Mopungite.
How to tell apart: Tripuhyite is the harder of the two (Mohs 6-7 vs. 5); streak differs, so Kyawthuite leaves white, Tripuhyite leaves canary-yellow to dark brown with a greenish tinge; luster reads adamantine on Kyawthuite and dull on Tripuhyite.
Often found alongside kyawthuite
Minerals reported to co-occur with kyawthuite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Bi³⁺Sb⁵⁺O₄
- Mohs hardness
- 5
- Density
- 8.256 g/cm³
- Colors
- Orange with red overtone
- Streak
- White
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Small tabular crystals
- Cleavage
- Perfect on {001}; good on {110} and {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Only known from alluvium, the presence of Bi, Sb and small amounts of Ta, as well as trace amounts of Ti, Nb, W and U, suggest an origin in a pegmatite
Where rockhounds find kyawthuite
Classic worldwide localities
- Mogok, Myanmar
Field-hunting tip
Where it forms: Only known from alluvium, the presence of Bi, Sb and small amounts of Ta, as well as trace amounts of Ti, Nb, W and U, suggest an origin in a pegmatite. If you start seeing quartz, topaz, beryl in float, you are in the right ground. Typical habit: small tabular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kyawthuite?+
Where is kyawthuite found?+
Is kyawthuite safe to handle?+
What rocks look like kyawthuite?+
What minerals are found with kyawthuite?+
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Find kyawthuite on the map
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