Middendorfite is a rare lead manganese silicate primarily found in the Långban mining district of Sweden. It typically occurs as small, bright orange fibrous masses or coatings within metamorphic manganese ores.
Is this middendorfite?
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 middendorfite with a known reference. Middendorfite sits at Mohs 4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Middendorfite leaves a yellowish streak.
- 3Read the lusterHold the specimen under a strong light. Middendorfite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: bright orange.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous aggregates.
Often confused with
Middendorfite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Hancockite is the harder of the two (Mohs 6-7 vs. 4); streak differs, so Middendorfite leaves yellowish, Hancockite leaves grayish white.
How to tell apart: Kentrolite is the harder of the two (Mohs 5 vs. 4); streak differs, so Middendorfite leaves yellowish, Kentrolite leaves yellowish-brown; luster reads vitreous on Middendorfite and vitreous to submetallic to greasy on Kentrolite.
Often found alongside middendorfite
Minerals reported to co-occur with middendorfite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₃Na₂Mn₅Si₁₂(O,OH)₃₆·2H₂O
- Mohs hardness
- 4
- Density
- 2.6 g/cm³
- Colors
- Streak
- Yellowish
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous Aggregates
- Cleavage
- Perfect {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphic Manganese Deposits
Where rockhounds find middendorfite
Classic worldwide localities
- Hilairite pegmatite, Khibiny alkaline pluton, Kola Peninsula, Russia
Field-hunting tip
Look in metamorphic manganese deposits country, the host setting where middendorfite typically forms. If you start seeing hausmannite, baryte, calcite in float, you are in the right ground. Field specimens usually show a fibrous aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify middendorfite?+
Where is middendorfite found?+
What rocks look like middendorfite?+
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Find middendorfite on the map
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