Manganhumite is a rare member of the Humite group characterized by its high manganese content compared to other members. It is typically found in metasomatized carbonate rocks or skarns, often forming granular aggregates with other silicates and carbonates.
Is this manganhumite?
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 manganhumite with a known reference. Manganhumite 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: subadamantine.
- 4Match the color rangeCompare against the expected color range: brown, brown orange, light orange.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: granular to massive.
Often confused with
Manganhumite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Chondrodite is the harder of the two (Mohs 6-6.5 vs. 4); streak differs, so Manganhumite leaves white, Chondrodite leaves gray; luster reads subadamantine on Manganhumite and vitreous to resinous on Chondrodite.
How to tell apart: Humite is the harder of the two (Mohs 6 vs. 4); luster reads subadamantine on Manganhumite and vitreous on Humite.
How to tell apart: Clinohumite is the harder of the two (Mohs 6 vs. 4); luster reads subadamantine on Manganhumite and vitreous on Clinohumite.
Often found alongside manganhumite
Minerals reported to co-occur with manganhumite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mn₇(SiO₄)₃(OH)₂
- Mohs hardness
- 4
- Density
- 3.83 g/cm³
- Streak
- White
- Luster
- Subadamantine
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Granular to massive
- Cleavage
- {001}, perfect
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- A late-stage skarn mineral formed in recrystallized limestone banded between layers of manganese ore minerals (Brattfors mine, Sweden)
Where rockhounds find manganhumite
Classic worldwide localities
- Bald Knob, near Sparta, Alleghany Co., North Carolina, and Franklin, Sussex Co., New Jersey, USA
- Brattfors mine, Nordmark, and at Långban, Värmland, Sweden
Field-hunting tip
Where it forms: A late-stage skarn mineral formed in recrystallized limestone banded between layers of manganese ore minerals (Brattfors mine, Sweden). If you start seeing katoptrite, magnetite, manganostibite in float, you are in the right ground. Typical habit: granular to massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify manganhumite?+
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What rocks look like manganhumite?+
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Find manganhumite on the map
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