Iriginite is a rare secondary uranium molybdenum mineral that typically forms as bright yellow earthy crusts or powdery coatings. It is an alteration product of primary ores and is highly sought after by radioactive mineral specialists for its distinct coloration and aesthetic occurrences in oxidation zones.
Is this iriginite?
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 iriginite with a known reference. Iriginite 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. Iriginite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Iriginite typically shows a earthy luster.
- 4Match the color rangeCompare against the expected color range: yellow, lemon-yellow, orange-yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: powdery, massive, or as crusts.
Often confused with
Iriginite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside iriginite
Minerals reported to co-occur with iriginite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- UO₂(MoO₄)(H₂O)₂
- Mohs hardness
- 2
- Density
- 4.56 g/cm³
- Streak
- Yellow
- Luster
- Earthy
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Powdery, Massive, Or as Crusts
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Uranium-molybdenum Deposits
- Typical price
- $50-200 for small samples
Where rockhounds find iriginite
Classic worldwide localities
- Kyzyl-Sai, Kazakhstan
- Shinkolobwe, DR Congo
- Eureka County, USA
Field-hunting tip
Look in oxidized zones of uranium-molybdenum deposits country — that is the host setting where iriginite typically forms. If you start seeing molybdite, uraninite, lermontovite in float, you are in the right ground. Field specimens usually show a powdery, massive, or as crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find iriginite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
