Magnesiocarpholite is a rare sorosilicate typically found as delicate, fibrous, or acicular aggregates in high-pressure metamorphic environments. Collectors often look for its characteristic silky luster and radial growth patterns, which distinguish it from more common fibrous silicates.
Is this magnesiocarpholite?
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 magnesiocarpholite with a known reference. Magnesiocarpholite sits at Mohs 5-5.5, 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: silky.
- 4Match the color rangeCompare against the expected color range: gray green, white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: columnar, fibrous.
Often confused with
Magnesiocarpholite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Magnesiocarpholite leaves white, Ferrocarpholite leaves greenish white.
How to tell apart: Luster reads silky on Magnesiocarpholite and vitreous on Tremolite.
Often found alongside magnesiocarpholite
Minerals reported to co-occur with magnesiocarpholite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MgAl₂Si₂O₆(OH)₄
- Mohs hardness
- 5-5.5
- Density
- 2.84-2.92 g/cm³
- Colors
- Streak
- White
- Luster
- Silky
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Columnar, fibrous
- Cleavage
- Good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In veins and in schist, quartzite, and metabauxite formed during high-pressure, low-temperature metamorphism (Vanoise, France)
Where rockhounds find magnesiocarpholite
Classic worldwide localities
- Vanoise massif, Savoie, France
- Found near Sfinari and Sisses, on Crete, Greece
Field-hunting tip
Where it forms: In veins and in schist, quartzite, and metabauxite formed during high-pressure, low-temperature metamorphism (Vanoise, France). If you start seeing chloritoid, pyrophyllite, paragonite in float, you are in the right ground. Typical habit: columnar, fibrous. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify magnesiocarpholite?+
Where is magnesiocarpholite found?+
What rocks look like magnesiocarpholite?+
What minerals are found with magnesiocarpholite?+
What kind of rock does magnesiocarpholite form in?+
What is magnesiocarpholite used for?+
Find magnesiocarpholite on the map
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