Middendorfite is a rare lead manganese silicate primarily found in the Långban mining district of Sweden. It typically occurs as small, dark brown to black 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 brown streak.
- 3Read the lusterHold the specimen under a strong light. Middendorfite typically shows a subadamantine luster.
- 4Match the color rangeCompare against the expected color range: dark brown, black.
- 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 — Middendorfite leaves brown, Hancockite leaves light brown; luster reads subadamantine on Middendorfite and vitreous on Hancockite.
How to tell apart: Kentrolite is the harder of the two (Mohs 5 vs. 4); streak differs — Middendorfite leaves brown, Kentrolite leaves yellowish-brown; luster reads subadamantine on Middendorfite and resinous 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
- Pb₂Mn₃(Si₂O₇)(OH)₂
- Mohs hardness
- 4
- Density
- 3.2 g/cm³
- Colors
- Streak
- Brown
- Luster
- Subadamantine
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphic Manganese Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find middendorfite
Classic worldwide localities
- Långban, Sweden
Field-hunting tip
Look in metamorphic manganese deposits country — that is 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
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Find middendorfite on the map
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