Bradaczekite is a rare copper sodium arsenate mineral discovered in the volcanic fumaroles of the Tolbachik volcano. It typically occurs as delicate, bright blue to greenish-blue tabular crystals or thin crusts in high-temperature volcanic environments.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrare

Bradaczekite

Hardness: 3
Luster: Vitreous
Streak: White
Transparency: Translucent

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Is this bradaczekite?

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 bradaczekite with a known reference. Bradaczekite sits at Mohs 3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Bradaczekite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Bradaczekite 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: monoclinic. Typical habit: tabular crystals, crusts, aggregates.

Often confused with

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

mineral

Lammerite

Mohs 3.5

How to tell apart: Streak differs — Bradaczekite leaves white, Lammerite leaves light green.

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Often found alongside bradaczekite

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

All properties

Chemical formula: NaCu₄(AsO₄)₃
Mohs hardness: 3
Density: 4.26 g/cm³
Colors: Blue Greenish-blue
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals, Crusts, Aggregates
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Fumarole Deposits
Typical price: $100-500 for small specimens

Where rockhounds find bradaczekite

Classic worldwide localities

Tolbachik volcano, Kamchatka, Russia

Field-hunting tip

Look in fumarole deposits country — that is the host setting where bradaczekite typically forms. If you start seeing lammerite, tenorite, hematite in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts, aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify bradaczekite?+

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

Where is bradaczekite found?+

Notable localities include Tolbachik volcano, Kamchatka, Russia.

How much is bradaczekite worth?+

Typical asking prices fall in the range of $100-500 for small specimens. Quality, size, and provenance can move individual specimens well outside that range.

Is bradaczekite safe to handle?+

It contains toxic constituents. Contains arsenic and 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 bradaczekite?+

Bradaczekite is most often confused with Lammerite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with bradaczekite?+

Bradaczekite commonly co-occurs with Lammerite, Tenorite, Hematite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does bradaczekite form in?+

Bradaczekite typically forms in fumarole deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is bradaczekite used for?+

Bradaczekite is used in collector.

Find bradaczekite on the map

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