Gravegliaite is a very rare manganese sulfite mineral typically found as delicate, colorless to white acicular needles. It is primarily known from the manganese mines in the Graveglia Valley of Italy, where it forms in small vugs or fractures within manganese-rich ores.
Is this gravegliaite?
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 gravegliaite with a known reference. Gravegliaite sits at Mohs 2.5, 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: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular or fibrous crystals forming radiating aggregates.
Often confused with
Gravegliaite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside gravegliaite
Minerals reported to co-occur with gravegliaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MnSO₃·3H₂O
- Mohs hardness
- 2.5
- Density
- 2.39 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular or fibrous crystals forming radiating aggregates
- Cleavage
- One II [010]
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Very rare, along fractures in metamorphosed manganiferous layers in radiolarian cherts in an ophiolite sequence
Where rockhounds find gravegliaite
Classic worldwide localities
- Gambatesa mine, near Reppia, Val Graveglia, Liguria, Italy
Field-hunting tip
Where it forms: Very rare, along fractures in metamorphosed manganiferous layers in radiolarian cherts in an ophiolite sequence. If you start seeing tephroite, bementite, braunite in float, you are in the right ground. Typical habit: acicular or fibrous crystals forming radiating aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify gravegliaite?+
Where is gravegliaite found?+
What rocks look like gravegliaite?+
What minerals are found with gravegliaite?+
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Find gravegliaite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
