Sayrite is a rare lead uranium hydroxide that forms yellow-orange to red-orange isolated prismatic crystals. It is an alteration product of uraninite in the oxidized zone of a uranium orebody. Associated minerals include uraninite, becquerelite and uranophane. It was first described from Shinkolobwe, Katanga Province, Congo (Shaba Province, Zaire).
Is this sayrite?
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 sayrite with a known reference. Sayrite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to adamantine.
- 4Match the color rangeCompare against the expected color range: yellow orange, red orange.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: isolated prismatic crystals.
Often confused with
Sayrite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Kasolite is the harder of the two (Mohs 4-5 vs. 2-3); streak differs, so Sayrite leaves yellow, Kasolite leaves pale yellow-brown; luster reads vitreous to adamantine on Sayrite and subadamantine to greasy, dull to earthy when massive on Kasolite.
How to tell apart: Streak differs, so Sayrite leaves yellow, Boltwoodite leaves white; luster reads vitreous to adamantine on Sayrite and pearly; radial aggregates vitreous to silky; dull to earthy in microcrystalline pseudomorphs on Boltwoodite.
Often found alongside sayrite
Minerals reported to co-occur with sayrite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₂(UO₂)₅O₆(OH)₂·4H₂O
- Mohs hardness
- 2-3
- Density
- 6.76 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Vitreous to adamantine
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Isolated prismatic crystals
- Cleavage
- {102}, distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An alteration product of uraninite in the oxidized zone of a uranium orebody
Where rockhounds find sayrite
Classic worldwide localities
- Shinkolobwe, Katanga Province, Congo (Shaba Province, Zaire)
Field-hunting tip
Where it forms: An alteration product of uraninite in the oxidized zone of a uranium orebody. If you start seeing uraninite, becquerelite, uranophane in float, you are in the right ground. Typical habit: isolated prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
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Find sayrite on the map
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