Ktenasite is a rare secondary copper-zinc sulfate mineral typically found as vibrant blue to blue-green platy crystals or thin crusts. It is most famous from the ancient mining district of Laurion, Greece, where it forms in the oxidation zones of ore bodies alongside other copper-zinc minerals.

Hardness

Mohs

Luster

Vitreous

Streak

Pale Blue

Transparency

Transparent

mineralrare

Ktenasite

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

Is this ktenasite?

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 ktenasite with a known reference. Ktenasite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Ktenasite leaves a pale blue streak.
3
Read the luster
Hold the specimen under a strong light. Ktenasite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: bright blue, blue-green.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy crystals, crusts, radial aggregates.

Often confused with

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

How to tell apart: Streak differs — Ktenasite leaves pale blue, Serpierite leaves white; luster reads vitreous on Ktenasite and pearly on Serpierite.

Compare →

Often found alongside ktenasite

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

All properties

Chemical formula: (Cu,Zn)₅(SO₄)₂(OH)₆·6H₂O
Mohs hardness: 2
Density: 3.17 g/cm³
Colors: Bright Blue Blue-green
Streak: Pale Blue
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Platy Crystals, Crusts, Radial Aggregates
Cleavage: Perfect On {001}
Rarity: Rare
Uses: Collector
Host rock: Oxidized Zones of Copper-zinc Deposits
Typical price: $20-150 for micro-mounts and small specimens

Where rockhounds find ktenasite

Classic worldwide localities

Kamariza mines, Laurion, Greece
Broken Hill, New South Wales, Australia
Kallmünz, Bavaria, Germany
Tsumeb, Namibia

Field-hunting tip

Look in oxidized zones of copper-zinc deposits country — that is the host setting where ktenasite typically forms. If you start seeing smithsonite, hemimorphite, brochantite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts, radial aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ktenasite?+

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

Where is ktenasite found?+

Notable localities include Kamariza mines, Laurion, Greece; Broken Hill, New South Wales, Australia; Kallmünz, Bavaria, Germany; Tsumeb, Namibia.

How much is ktenasite worth?+

Typical asking prices fall in the range of $20-150 for micro-mounts and small specimens. Quality, size, and provenance can move individual specimens well outside that range.

Is ktenasite safe to handle?+

It contains toxic constituents. Contains copper and zinc; wash hands after handling to avoid ingestion or skin irritation. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like ktenasite?+

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

What minerals are found with ktenasite?+

Ktenasite commonly co-occurs with Smithsonite, Hemimorphite, Brochantite, Aurichalcite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does ktenasite form in?+

Ktenasite typically forms in oxidized zones of copper-zinc deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is ktenasite used for?+

Ktenasite is used in collector.

Find ktenasite on the map

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