Olivenite is a secondary copper arsenate mineral typically found in the oxidized zones of copper deposits. It is highly valued by collectors for its vibrant olive-green color and sharp, prismatic crystals, though it is also commonly found in attractive botryoidal or fibrous habits known as 'wood copper'.
Is this olivenite?
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 olivenite with a known reference. Olivenite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: olive-green to brown.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine to vitreous, pearly to silky if fibrous.
- 4Match the color rangeCompare against the expected color range: olive green, yellowish brown, dirty white, blackish green, liver brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic, radial, reniform.
Often confused with
Olivenite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Adelite is the harder of the two (Mohs 5 vs. 3); streak differs, so Olivenite leaves olive-green to brown, Adelite leaves white; luster reads adamantine to vitreous, pearly to silky if fibrous on Olivenite and resinous on Adelite.
How to tell apart: Austinite is the harder of the two (Mohs 4-4.5 vs. 3); streak differs, so Olivenite leaves olive-green to brown, Austinite leaves white; luster reads adamantine to vitreous, pearly to silky if fibrous on Olivenite and subadamantine to silky in aggregates on Austinite.
How to tell apart: Streak differs, so Olivenite leaves olive-green to brown, Clinoclase leaves bluish green; luster reads adamantine to vitreous, pearly to silky if fibrous on Olivenite and vitreous, pearly on cleavages on Clinoclase.
Often found alongside olivenite
Minerals reported to co-occur with olivenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₂AsO₄OH
- Mohs hardness
- 3
- Density
- 4.46 g/cm³
- Colors
- Streak
- Olive-green to brown
- Luster
- Adamantine to vitreous, pearly to silky if fibrous
- Transparency
- Translucent to opaque
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic, radial, reniform
- Cleavage
- {101}, {110}, indistinct
- Rarity
- Uncommon
- Uses
- Collector, Mineral specimens
- Host rock
- The most common secondary copper arsenate in the oxdized zone of hydrothermal copper deposits
Where rockhounds find olivenite
Classic worldwide localities
- Mammoth, American Eagle, and other mines in the Tintic district, Juab Co., Utah, USA
- Majuba Hill mine, Antelope district, Pershing Co., Nevada, USA
- Cornwall, at the Carharrack mine, Wheals Gorland, Unity, and others in Gwennap, Linkinhorne, England
- Alston Moor, Cumbria, and Tavistock, Devon, England
- Cap Garonne mine, near le Pradet, Var, France
- Clara Mine, near Oberwolfach, and many other places in the Black Forest, Germany
Field-hunting tip
Where it forms: The most common secondary copper arsenate in the oxdized zone of hydrothermal copper deposits. If you start seeing conichalcite, clinoclase, tyrolite in float, you are in the right ground. Typical habit: prismatic, radial, reniform. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify olivenite?+
Where is olivenite found?+
Is olivenite safe to handle?+
What rocks look like olivenite?+
What minerals are found with olivenite?+
What kind of rock does olivenite form in?+
What is olivenite used for?+
Find olivenite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
