Kutinaite is a rare copper-silver intermetallic mineral that typically occurs in massive or granular forms within silver-rich hydrothermal vein deposits. It is best identified through polished sections under reflected light microscopy due to its metallic luster and association with other silver-antimony minerals.

Hardness

3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Kutinaite

Hardness: 3.5
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this kutinaite?

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 kutinaite with a known reference. Kutinaite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Kutinaite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Kutinaite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: silver-white, pale brass-yellow.
5
Look at form & habit
Crystal system: cubic. Typical habit: massive, granular.

Often confused with

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

How to tell apart: Streak differs — Kutinaite leaves black, Allargentum leaves silver-white.

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Often found alongside kutinaite

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

All properties

Chemical formula: Cu₄Ag₃
Mohs hardness: 3.5
Density: 8.8 g/cm³
Colors: Silver-white Pale Brass-yellow
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Massive, Granular
Cleavage: None
Rarity: Rare
Uses: Collector, Research
Host rock: Hydrothermal Silver-lead Veins
Typical price: $50-300 per specimen depending on size and rarity

Where rockhounds find kutinaite

Classic worldwide localities

Kutná Hora, Czech Republic
Cobalt, Ontario, Canada
Saganoseki, Japan

Field-hunting tip

Look in hydrothermal silver-lead veins country — that is the host setting where kutinaite typically forms. If you start seeing dyscrasite, silver, galena in float, you are in the right ground. Field specimens usually show a massive, granular habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify kutinaite?+

Mohs hardness is 3.5. It typically shows a metallic luster. The streak is black. Common colors include silver-white, pale brass-yellow.

Where is kutinaite found?+

Notable localities include Kutná Hora, Czech Republic; Cobalt, Ontario, Canada; Saganoseki, Japan.

How much is kutinaite worth?+

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

Is kutinaite safe to handle?+

It contains toxic constituents. Contains copper and silver, but the primary concern is the potential for associated toxic elements in similar deposits; wash hands after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like kutinaite?+

Kutinaite is most often confused with Dyscrasite, Allargentum. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with kutinaite?+

Kutinaite commonly co-occurs with Dyscrasite, Silver, Galena, Sphalerite, Pyrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kutinaite form in?+

Kutinaite typically forms in hydrothermal silver-lead veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is kutinaite used for?+

Kutinaite is used in collector, research.

Find kutinaite on the map

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