Carrboydite is a rare secondary mineral typically found as botryoidal coatings or crusts in the oxidized zones of nickel sulfide deposits. It is often identified by its distinct pale green color and its association with weathered nickel-bearing minerals. Collectors prize it for its unique, though delicate, crystalline morphology found in specific arid Australian mining regions.
Is this carrboydite?
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 carrboydite with a known reference. Carrboydite 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. Carrboydite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Carrboydite typically shows a earthy luster.
- 4Match the color rangeCompare against the expected color range: green, pale green, bluish-green.
- 5Look at form & habitCrystal system: trigonal. Typical habit: botryoidal, crusts, coatings.
Often confused with
Carrboydite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads earthy on Carrboydite and pearly on Woodwardite.
How to tell apart: Luster reads earthy on Carrboydite and vitreous on Goslarite.
How to tell apart: Luster reads earthy on Carrboydite and vitreous on Morenosite.
Often found alongside carrboydite
Minerals reported to co-occur with carrboydite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ni,Cu)₆Al₃(SO₄,CO₃,OH)₁₈·3-4H₂O
- Mohs hardness
- 2
- Density
- 2.1-2.2 g/cm³
- Streak
- White
- Luster
- Earthy
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Botryoidal, Crusts, Coatings
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Nickel-bearing Sulfide Deposits
- Typical price
- $50-300 per specimen depending on size and quality
Where rockhounds find carrboydite
Classic worldwide localities
- Carr Boyd Rocks, Western Australia
- Agnew, Western Australia
- Sierra Gorda, Chile
Field-hunting tip
Look in oxidized zones of nickel-bearing sulfide deposits country — that is the host setting where carrboydite typically forms. If you start seeing goethite, glaucodot, magnetite in float, you are in the right ground. Field specimens usually show a botryoidal, crusts, coatings habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify carrboydite?+
Where is carrboydite found?+
How much is carrboydite worth?+
Is carrboydite safe to handle?+
What rocks look like carrboydite?+
What minerals are found with carrboydite?+
What kind of rock does carrboydite form in?+
What is carrboydite used for?+
Find carrboydite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
