Mandarinoite is a rare hydrated iron selenite mineral that typically forms as delicate, transparent, yellow-green blades or crusts. It is most often found in association with other selenium minerals in oxidized zones of hydrothermal deposits. Because of its rarity and sensitivity to atmospheric conditions, it is highly sought after by advanced systematic mineral collectors.
Is this mandarinoite?
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 mandarinoite with a known reference. Mandarinoite 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. Mandarinoite leaves a pale yellow streak.
- 3Read the lusterHold the specimen under a strong light. Mandarinoite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: bladed, tabular, or as crusts.
Often confused with
Mandarinoite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside mandarinoite
Minerals reported to co-occur with mandarinoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₂Se₃O₉·6H₂O
- Mohs hardness
- 2
- Density
- 2.8 g/cm³
- Colors
- Streak
- Pale Yellow
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Bladed, Tabular, Or as Crusts
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Selenium-rich Veins
- Typical price
- $50-500 thumbnail depending on matrix
Where rockhounds find mandarinoite
Classic worldwide localities
- Honneko-dani, Japan
- Pacajake mine, Bolivia
- Sierra Gorda, Chile
Field-hunting tip
Look in hydrothermal selenium-rich veins country — that is the host setting where mandarinoite typically forms. If you start seeing penroseite, chalcomenite, goethite in float, you are in the right ground. Field specimens usually show a bladed, tabular, or as crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify mandarinoite?+
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How much is mandarinoite worth?+
Is mandarinoite safe to handle?+
What rocks look like mandarinoite?+
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Find mandarinoite on the map
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