Nakauriite is a rare hydrated copper nickel sulfate that typically forms as soft, sky-blue fibrous crusts or tiny needle-like aggregates. It is almost exclusively found in association with serpentinite environments, often appearing as an alteration product of primary ore minerals.

Hardness

2-3

Mohs

Luster

Dull

Streak

White

Transparency

Opaque

mineralrare

Nakauriite

Hardness: 2-3
Luster: Dull
Streak: White
Transparency: Opaque

Is this nakauriite?

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 nakauriite with a known reference. Nakauriite 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. Nakauriite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Nakauriite typically shows a dull luster.
4
Match the color range
Compare against the expected color range: blue, pale blue, bluish green.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: fibrous.

Often confused with

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

mineral

Chrysocolla

Mohs 2-4

How to tell apart: Luster reads dull on Nakauriite and vitreous on Chrysocolla.

How to tell apart: Streak differs — Nakauriite leaves white, Langite leaves pale blue; luster reads dull on Nakauriite and vitreous on Langite.

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Often found alongside nakauriite

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

Serpentine
mineral · Mohs 2.5-5.5

All properties

Chemical formula: (Cu,Ni,Mg)₄(SO₄)(OH)₆·48H₂O
Mohs hardness: 2-3
Density: 2.1-2.3 g/cm³
Colors: Blue Pale Blue Bluish Green
Streak: White
Luster: Dull
Transparency: Opaque
Crystal system: Orthorhombic
Crystal habit: Fibrous
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Ultramafic Rocks
Typical price: $50-300 per specimen

Where rockhounds find nakauriite

Classic worldwide localities

Nakauri mine, Japan
Sierra Nevada, Spain
Aosta Valley, Italy

Field-hunting tip

Look in ultramafic rocks country — that is the host setting where nakauriite typically forms. If you start seeing serpentine, nickel-bearing minerals in float, you are in the right ground. Field specimens usually show a fibrous habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify nakauriite?+

Mohs hardness is 2-3. It typically shows a dull luster. The streak is white. Common colors include blue, pale blue, bluish green.

Where is nakauriite found?+

Notable localities include Nakauri mine, Japan; Sierra Nevada, Spain; Aosta Valley, Italy.

How much is nakauriite 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 nakauriite safe to handle?+

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

What rocks look like nakauriite?+

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

What minerals are found with nakauriite?+

Nakauriite commonly co-occurs with Serpentine, Nickel-bearing minerals. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does nakauriite form in?+

Nakauriite typically forms in ultramafic rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is nakauriite used for?+

Nakauriite is used in collector.

Find nakauriite on the map

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