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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
3
Mohs
Luster
Adamantine
Streak
Light blue to white
Transparency
Transparent

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. Streak: light blue to white.
  • 3
    Read the luster
    Hold the specimen under a strong light. Luster: adamantine.
  • 4
    Match the color range
    Compare against the expected color range: dark blue.
  • 5
    Look at form & habit
    Crystal system: monoclinic. Typical habit: aggregates.

Often confused with

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

Lammerite mineral
mineral
Lammerite
Mohs 3-4

How to tell apart: Luster reads adamantine on Bradaczekite and vitreous on Lammerite.

Compare →

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
4.77 g/cm³
Colors
Dark blue
Streak
Light blue to white
Luster
Adamantine
Transparency
Transparent
Crystal system
Monoclinic
Crystal habit
Aggregates
Cleavage
None
Rarity
Rare
Uses
Collector
Host rock
Formed in a volcanic fumarole

Where rockhounds find bradaczekite

Classic worldwide localities

  • North Breach of the Tolbachik Great fissure eruption, Kamchatka Peninsula, Russia (type locality)

Field-hunting tip

Where it forms: Formed in a volcanic fumarole. If you start seeing hematite, tenorite, lammerite in float, you are in the right ground. Typical habit: aggregates. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify bradaczekite?+
Mohs hardness is 3. Luster: adamantine. The streak is light blue to white. Common colors include dark blue.
Where is bradaczekite found?+
Notable localities include North Breach of the Tolbachik Great fissure eruption, Kamchatka Peninsula, Russia (type locality).
Is bradaczekite safe to handle?+
Bradaczekite contains arsenic and copper and calls for real care. Contains arsenic and copper; wash hands thoroughly after handling and avoid inhaling dust.
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 Hematite, Tenorite, Lammerite, Urusovite, Orthoclase, Johillerite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does bradaczekite form in?+
Where it forms: Formed in a volcanic fumarole. 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

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