Tyrolite is a secondary copper arsenate mineral typically found as attractive apple-green to blue-green foliated crusts or small tabular crystal groups. It forms in the oxidized zones of copper deposits and is highly prized by collectors for its distinctive pearly luster and delicate radial habits.
Is this tyrolite?
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 tyrolite with a known reference. Tyrolite 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. Streak: pale green or pale blue.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous, pearly on cleavages.
- 4Match the color rangeCompare against the expected color range: blue, blue green, green blue, light green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: botryoidal, platy, radial.
Often confused with
Tyrolite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Tyrolite leaves pale green or pale blue, Aurichalcite leaves light blue; luster reads vitreous, pearly on cleavages on Tyrolite and silky to pearly on Aurichalcite.
How to tell apart: Malachite is the harder of the two (Mohs 3.5-4 vs. ~2); luster reads vitreous, pearly on cleavages on Tyrolite and adamantine to vitreous; silky if fibrous; dull to earthy if massive on Malachite.
How to tell apart: Conichalcite is the harder of the two (Mohs 4.5 vs. ~2); streak differs, so Tyrolite leaves pale green or pale blue, Conichalcite leaves green.
Often found alongside tyrolite
Minerals reported to co-occur with tyrolite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂Cu₉(AsO₄)₄(CO₃)(OH)₈·11H₂O
- Mohs hardness
- ~2
- Density
- 3.25 g/cm³
- Streak
- Pale green or pale blue
- Luster
- Vitreous, pearly on cleavages
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Botryoidal, platy, radial
- Cleavage
- On {001}, perfect, micaceous
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- An uncommon secondary mineral in the oxidized zone of hydrothermal copper deposits, typically formed by alteration of tennantite
Where rockhounds find tyrolite
Classic worldwide localities
- Centennial Eureka, Mammoth, and other mines, Tintic district, Juab Co., and the Gold Hill mine, Tooele Co., Utah, USA
- Majuba Hill mine, Antelope district, Pershing Co., Nevada, USA
- Tirol, on the Falkenstein, near Schwaz, Austria
- Kogel, near Brixlegg, Austria
- Rattenberg, Austria
- L’ubietová, near Baňská Bystrica (Libethen, near Neusohl), Slovakia
Field-hunting tip
Where it forms: An uncommon secondary mineral in the oxidized zone of hydrothermal copper deposits, typically formed by alteration of tennantite. If you start seeing tennantite, malachite, azurite in float, you are in the right ground. Typical habit: botryoidal, platy, radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tyrolite?+
Where is tyrolite found?+
Is tyrolite safe to handle?+
What rocks look like tyrolite?+
What minerals are found with tyrolite?+
What kind of rock does tyrolite form in?+
What is tyrolite used for?+
Find tyrolite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
