Sonolite is a rare manganese silicate member of the humite group, typically found in metamorphosed manganese deposits. It is best identified by its characteristic bright yellow fluorescence under UV light, which helps distinguish it from other chemically similar humite group minerals.
Is this sonolite?
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 sonolite with a known reference. Sonolite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Sonolite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Sonolite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, orange, brownish-red.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: granular to massive, rarely as distinct tabular crystals.
Often confused with
Sonolite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside sonolite
Minerals reported to co-occur with sonolite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mn₉(SiO₄)₄(F,OH)₂
- Mohs hardness
- 6
- Density
- 3.37 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Granular to Massive, Rarely as Distinct Tabular Crystals
- Cleavage
- Poor in One Direction
- Fluorescence
- Bright Yellow Under SW and LW UV
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Metamorphosed Manganese-rich Sedimentary Deposits
- Typical price
- $20-150 for thumbnail to small cabinet specimens
Where rockhounds find sonolite
Classic worldwide localities
- Tanohata mine, Japan
- Franklin, New Jersey, USA
- Langban, Sweden
Field-hunting tip
Look in metamorphosed manganese-rich sedimentary deposits country — that is the host setting where sonolite typically forms. If you start seeing friedelite, hancockite, willemite in float, you are in the right ground. Field specimens usually show a granular to massive, rarely as distinct tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find sonolite on the map
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