Magnioursilite is a rare secondary uranium mineral that typically forms as soft, earthy, or powdery coatings on other uranium-bearing ores. It is primarily identified in oxidation zones of uranium deposits and requires careful handling due to its inherent radioactivity.
Is this magnioursilite?
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 magnioursilite with a known reference. Magnioursilite 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. Magnioursilite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Magnioursilite typically shows a earthy luster.
- 4Match the color rangeCompare against the expected color range: yellow, pale yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: powdery, earthy crusts.
Often confused with
Magnioursilite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Magnioursilite leaves yellow, Uranophane leaves pale yellow; luster reads earthy on Magnioursilite and vitreous on Uranophane.
How to tell apart: Luster reads earthy on Magnioursilite and pearly on Boltwoodite.
Often found alongside magnioursilite
Minerals reported to co-occur with magnioursilite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg(UO₂)₂(SiO₃OH)₂(OH)₂·5H₂O
- Mohs hardness
- 2-3
- Density
- 3.5-3.8 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Earthy
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Powdery, Earthy Crusts
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Uranium Deposits
- Typical price
- $50-300 for small radioactive mineral specimens
Where rockhounds find magnioursilite
Classic worldwide localities
- Shinkolobwe, Democratic Republic of the Congo
- Jáchymov, Czech Republic
Field-hunting tip
Look in oxidized uranium deposits country, the host setting where magnioursilite typically forms. If you start seeing uraninite, becquerelite, curite in float, you are in the right ground. Field specimens usually show a powdery, earthy crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify magnioursilite?+
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Is magnioursilite safe to handle?+
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Find magnioursilite on the map
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