Ganophyllite is a rare manganese phyllosilicate mineral characterized by its distinct pearly luster and perfect micaceous cleavage. It is typically found as brown, foliated masses or platy crystals within metamorphosed manganese ore bodies, often appearing alongside other manganese-rich minerals like jacobsite.
Is this ganophyllite?
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 ganophyllite with a known reference. Ganophyllite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Ganophyllite leaves a yellowish-brown streak.
- 3Read the lusterHold the specimen under a strong light. Ganophyllite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: brown, yellowish-brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, foliated masses.
Often confused with
Ganophyllite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside ganophyllite
Minerals reported to co-occur with ganophyllite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (K,Na,Ca)₂(Mn,Al,Mg)₈(Si,Al)₁₂O₂₉(OH,O)₇·8H₂O
- Mohs hardness
- 3-4
- Density
- 2.8 g/cm³
- Colors
- Streak
- Yellowish-brown
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals, Foliated Masses
- Cleavage
- Perfect Basal
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphosed Manganese Deposits
- Typical price
- $20-150 thumbnail
Where rockhounds find ganophyllite
Classic worldwide localities
- Harstig Mine, Sweden
- Franklin, New Jersey, USA
- Molinello Mine, Italy
- Kaso Mine, Japan
Field-hunting tip
Look in metamorphosed manganese deposits country — that is the host setting where ganophyllite typically forms. If you start seeing jacobsite, hausmannite, bustamite in float, you are in the right ground. Field specimens usually show a platy crystals, foliated masses habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find ganophyllite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
