Masuyite is a rare secondary uranium mineral often found as attractive orange to reddish-orange platy crystal aggregates. It typically forms through the alteration of uraninite in the oxidation zones of uranium deposits and requires careful handling due to its radioactive nature.
Is this masuyite?
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 masuyite with a known reference. Masuyite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Masuyite leaves a orange-yellow streak.
- 3Read the lusterHold the specimen under a strong light. Masuyite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: orange, red, reddish-orange.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: platy crystals, prismatic, crusts.
Often confused with
Masuyite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Masuyite leaves orange-yellow, Curite leaves orange.
How to tell apart: Streak differs — Masuyite leaves orange-yellow, Vandenbrandeite leaves light green; luster reads adamantine on Masuyite and vitreous on Vandenbrandeite.
Often found alongside masuyite
Minerals reported to co-occur with masuyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb(UO₂)₃O₃(OH)₂·3H₂O
- Mohs hardness
- 3-4
- Density
- 5.26 g/cm³
- Colors
- Streak
- Orange-yellow
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Platy Crystals, Prismatic, Crusts
- Cleavage
- Perfect in One Direction
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Uranium-rich Hydrothermal Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find masuyite
Classic worldwide localities
- Shinkolobwe Mine, DR Congo
- Musonoi Mine, DR Congo
- Rabejac Mine, France
- Krunkelbachtal, Germany
Field-hunting tip
Look in oxidized zones of uranium-rich hydrothermal deposits country — that is the host setting where masuyite typically forms. If you start seeing curite, becquerelite, fourmarierite in float, you are in the right ground. Field specimens usually show a platy crystals, prismatic, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find masuyite on the map
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