Comblainite is a rare nickel-cobalt carbonate mineral occurring as small, delicate platy crystals or thin crusts. It is typically found in weathered limestone environments and is highly prized by collectors for its distinct, vibrant yellow to brownish-yellow color and rarity.
Is this comblainite?
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 comblainite with a known reference. Comblainite 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. Comblainite leaves a yellowish-white streak.
- 3Read the lusterHold the specimen under a strong light. Comblainite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: yellow, brownish-yellow, brown.
- 5Look at form & habitCrystal system: trigonal. Typical habit: platy crystals, crusts, radial aggregates.
Often confused with
Comblainite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Comblainite leaves yellowish-white, Hydrotalcite leaves white.
How to tell apart: Streak differs — Comblainite leaves yellowish-white, Stichtite leaves white; luster reads pearly on Comblainite and waxy on Stichtite.
Often found alongside comblainite
Minerals reported to co-occur with comblainite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ni₄Co₂(OH)₁₂(CO₃)·3H₂O
- Mohs hardness
- 2
- Density
- 2.44 g/cm³
- Streak
- Yellowish-white
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Platy Crystals, Crusts, Radial Aggregates
- Cleavage
- Perfect Basal
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Ore Deposits in Limestone
- Typical price
- $50-300 per specimen
Where rockhounds find comblainite
Classic worldwide localities
- Comblain-au-Pont, Belgium
- Bou Azzer, Morocco
Field-hunting tip
Look in oxidized ore deposits in limestone country — that is the host setting where comblainite typically forms. If you start seeing calcite, dolomite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts, radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify comblainite?+
Where is comblainite found?+
How much is comblainite worth?+
Is comblainite safe to handle?+
What rocks look like comblainite?+
What minerals are found with comblainite?+
What kind of rock does comblainite form in?+
What is comblainite used for?+
Find comblainite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
