Chromceladonite is a rare chromium-bearing member of the celadonite group, often appearing as soft, powdery green fillings in basaltic vugs. Collectors primarily look for it in volcanic regions where it forms as a secondary mineral in association with zeolite minerals.
Is this chromceladonite?
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 chromceladonite with a known reference. Chromceladonite sits at Mohs 1-2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to silky.
- 4Match the color rangeCompare against the expected color range: emerald green, dark green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive, spherical.
Often confused with
Chromceladonite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Chromceladonite leaves pale green, Glauconite leaves light green; luster reads vitreous to silky on Chromceladonite and dull, glistening on Glauconite.
How to tell apart: Streak differs, so Chromceladonite leaves pale green, Celadonite leaves greenish white; luster reads vitreous to silky on Chromceladonite and dull on Celadonite.
Often found alongside chromceladonite
Minerals reported to co-occur with chromceladonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KMgCr(Si₄O₁₀)(OH)₂
- Mohs hardness
- 1-2
- Density
- 2.90 g/cm³
- Colors
- Streak
- Pale green
- Luster
- Vitreous to silky
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Massive, spherical
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A metasomatic-hydrothermal mineral
Where rockhounds find chromceladonite
Classic worldwide localities
- Padma uranium-vanadium deposit, southern Karelia, Russia
Field-hunting tip
Where it forms: A metasomatic-hydrothermal mineral. If you start seeing dolomite, quartz, roscoelite in float, you are in the right ground. Typical habit: massive, spherical. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify chromceladonite?+
Where is chromceladonite found?+
What rocks look like chromceladonite?+
What minerals are found with chromceladonite?+
What kind of rock does chromceladonite form in?+
What is chromceladonite used for?+
Find chromceladonite on the map
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