Koutekite is a rare copper-arsenic mineral that typically forms as anhedral masses within hydrothermal vein deposits. It is known for its metallic luster and distinctive silver-white color, which may quickly tarnish to a duller hue upon exposure to air.

Hardness

3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Koutekite

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

Is this koutekite?

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 koutekite with a known reference. Koutekite 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. Koutekite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Koutekite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: white, silver-white, pinkish-white.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: massive, anhedral grains.

Often confused with

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

mineral

Domeykite

Mohs 3-3.5

How to tell apart: Streak differs — Koutekite leaves black, Domeykite leaves metallic white.

How to tell apart: Streak differs — Koutekite leaves black, Algodonite leaves white.

Often found alongside koutekite

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

All properties

Chemical formula: Cu₅As₂
Mohs hardness: 3.5
Density: 8.5 g/cm³
Colors: White Silver-white Pinkish-white
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Hexagonal
Crystal habit: Massive, Anhedral Grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $50-300 per specimen

Where rockhounds find koutekite

Classic worldwide localities

Bou-Azzer, Morocco
Kutná Hora, Czech Republic
Saxony, Germany

Field-hunting tip

Look in hydrothermal veins country — that is the host setting where koutekite typically forms. If you start seeing domeykite, algodonite, native arsenic in float, you are in the right ground. Field specimens usually show a massive, anhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify koutekite?+

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

Where is koutekite found?+

Notable localities include Bou-Azzer, Morocco; Kutná Hora, Czech Republic; Saxony, Germany.

How much is koutekite worth?+

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

Is koutekite safe to handle?+

It contains toxic constituents. Contains arsenic, which is toxic; handle with care and wash hands thoroughly after contact to avoid ingestion or inhalation of dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like koutekite?+

Koutekite is most often confused with Domeykite, Algodonite, Arsenic. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with koutekite?+

Koutekite commonly co-occurs with Domeykite, Algodonite, Native Arsenic, Nickeline. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does koutekite form in?+

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

What is koutekite used for?+

Koutekite is used in collector.

Find koutekite on the map

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