Manganilvaite is a rare manganese-rich member of the ilvaite group, typically occurring in dark, submetallic prismatic crystals. It is most frequently found in skarn deposits where limestone has been altered by hydrothermal activity and igneous intrusions. Collectors identify it by its specific habit and association with other contact metamorphic minerals, often requiring chemical testing to distinguish from standard ilvaite.
Is this manganilvaite?
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 manganilvaite with a known reference. Manganilvaite sits at Mohs 5.5-6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Manganilvaite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Manganilvaite typically shows a submetallic luster.
- 4Match the color rangeCompare against the expected color range: black, brownish-black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, massive.
Often confused with
Manganilvaite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside manganilvaite
Minerals reported to co-occur with manganilvaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaFe²⁺Fe³⁺Mn²⁺(Si₂O₇)O(OH)
- Mohs hardness
- 5.5-6
- Density
- 4.0-4.1 g/cm³
- Colors
- Streak
- Black
- Luster
- Submetallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Massive
- Cleavage
- Distinct in One Direction
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Skarn Deposits, Contact Metamorphic Rocks
- Typical price
- $20-150 for small specimens
Where rockhounds find manganilvaite
Classic worldwide localities
- Elba, Italy
- Seriphos, Greece
- Hebei Province, China
Field-hunting tip
Look in skarn deposits, contact metamorphic rocks country — that is the host setting where manganilvaite typically forms. If you start seeing quartz, calcite, epidote in float, you are in the right ground. Field specimens usually show a prismatic crystals, massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find manganilvaite on the map
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