Montetrisaite is a rare copper sulfate carbonate mineral primarily found in the oxidized zones of copper mines. It typically occurs as delicate, acicular blue crystal aggregates and is prized by micromount collectors for its distinctive color and association with other secondary copper minerals.

Hardness

2-3

Mohs

Luster

Vitreous

Streak

Pale Blue

Transparency

Transparent

mineralrare

Montetrisaite

Hardness: 2-3
Luster: Vitreous
Streak: Pale Blue
Transparency: Transparent

No image

Is this montetrisaite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch montetrisaite with a known reference. Montetrisaite sits at Mohs 2-3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Montetrisaite leaves a pale blue streak.
3
Read the luster
Hold the specimen under a strong light. Montetrisaite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: blue, greenish blue.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: acicular to prismatic crystals.

Often confused with

Montetrisaite vs. its common look-alikes — and how to tell them apart in the field.

How to tell apart: Streak differs — Montetrisaite leaves pale blue, Brochantite leaves pale-green.

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Often found alongside montetrisaite

Minerals reported to co-occur with montetrisaite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: Cu₆[(OH)₈|SO₄|CO₃]·2H₂O
Mohs hardness: 2-3
Density: 3.37 g/cm³
Colors: Blue Greenish Blue
Streak: Pale Blue
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Acicular to Prismatic Crystals
Cleavage: Good in One Direction
Rarity: Rare
Uses: Collector
Host rock: Oxidized Hydrothermal Copper Deposits
Typical price: $50-300 per specimen depending on size and quality

Where rockhounds find montetrisaite

Classic worldwide localities

Sa Duchessa mine, Sardinia, Italy

Field-hunting tip

Look in oxidized hydrothermal copper deposits country — that is the host setting where montetrisaite typically forms. If you start seeing malachite, brochantite, langite in float, you are in the right ground. Field specimens usually show a acicular to prismatic crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify montetrisaite?+

Mohs hardness is 2-3. It typically shows a vitreous luster. The streak is pale blue. Common colors include blue, greenish blue.

Where is montetrisaite found?+

Notable localities include Sa Duchessa mine, Sardinia, Italy.

How much is montetrisaite worth?+

Typical asking prices fall in the range of $50-300 per specimen depending on size and quality. Quality, size, and provenance can move individual specimens well outside that range.

Is montetrisaite safe to handle?+

It contains toxic constituents. Contains copper; wash hands thoroughly after handling and avoid inhaling dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like montetrisaite?+

Montetrisaite is most often confused with Devilline, Posnjakite, Brochantite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with montetrisaite?+

Montetrisaite commonly co-occurs with Malachite, Brochantite, Langite, Posnjakite, Gypsum. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does montetrisaite form in?+

Montetrisaite typically forms in oxidized hydrothermal copper deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is montetrisaite used for?+

Montetrisaite is used in collector.

Find montetrisaite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.