Ferroceladonite is a phyllosilicate mineral occurring primarily as earthy or micaceous coatings within the vesicles of volcanic rocks. It is visually distinguished from standard celadonite by its iron-dominant composition and is most frequently collected as an attractive green filling in basalt cavities.
Is this ferroceladonite?
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 ferroceladonite with a known reference. Ferroceladonite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Ferroceladonite leaves a pale green streak.
- 3Read the lusterHold the specimen under a strong light. Ferroceladonite typically shows a dull luster.
- 4Match the color rangeCompare against the expected color range: blue-green, green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive, earthy, micaceous coatings.
Often confused with
Ferroceladonite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Ferroceladonite leaves pale green, Celadonite leaves white.
How to tell apart: Streak differs, so Ferroceladonite leaves pale green, Chlorite leaves white; luster reads dull on Ferroceladonite and pearly on Chlorite.
Often found alongside ferroceladonite
Minerals reported to co-occur with ferroceladonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KFe³⁺(Fe²⁺,Mg)(Si₄O₁₀)(OH)₂
- Mohs hardness
- 2
- Density
- 2.8-3.0 g/cm³
- Colors
- Streak
- Pale Green
- Luster
- Dull
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Massive, Earthy, Micaceous Coatings
- Cleavage
- Perfect Basal
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Amygdaloidal Basalt
- Typical price
- $10-50 per specimen
Where rockhounds find ferroceladonite
Classic worldwide localities
- Azores
- Iceland
- Italy
- India
Field-hunting tip
Look in amygdaloidal basalt country, the host setting where ferroceladonite typically forms. If you start seeing heulandite, stilbite, calcite in float, you are in the right ground. Field specimens usually show a massive, earthy, micaceous coatings habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ferroceladonite?+
Where is ferroceladonite found?+
How much is ferroceladonite worth?+
What rocks look like ferroceladonite?+
What minerals are found with ferroceladonite?+
What kind of rock does ferroceladonite form in?+
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Find ferroceladonite on the map
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