Zálesíite is a rare arsenate mineral belonging to the Mixite group, typically found as delicate, needle-like crystals or radial sprays. It is often identified in oxidized zones of arsenic-rich deposits, distinguished primarily through chemical analysis due to its visual similarity to other members of the Mixite group.

Hardness

3-4

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareMixite Group family

Zálesíite

Hardness: 3-4
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this zálesíite?

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 zálesíite with a known reference. Zálesíite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Zálesíite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Zálesíite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: green, pale green, white.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: acicular or fibrous radial sprays.

Often confused with

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

How to tell apart: Streak differs — Zálesíite leaves white, Parnauite leaves pale blue.

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Often found alongside zálesíite

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

All properties

Chemical formula: CaCu₆(AsO₄)₃(OH)₆·3H₂O
Mohs hardness: 3-4
Density: 3.85 g/cm³
Colors: Green Pale Green White
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Hexagonal
Crystal habit: Acicular or Fibrous Radial Sprays
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins in Metamorphic Rocks
Typical price: $50-300 per specimen

Where rockhounds find zálesíite

Classic worldwide localities

Zálesí, Czech Republic
Schwarzwald, Germany
Chile
Greece

Field-hunting tip

Look in hydrothermal veins in metamorphic rocks country — that is the host setting where zálesíite typically forms. If you start seeing arsenopyrite, erythrite, conichalcite in float, you are in the right ground. Field specimens usually show a acicular or fibrous radial sprays habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify zálesíite?+

Mohs hardness is 3-4. It typically shows a vitreous luster. The streak is white. Common colors include green, pale green, white.

Where is zálesíite found?+

Notable localities include Zálesí, Czech Republic; Schwarzwald, Germany; Chile; Greece.

How much is zálesíite 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 zálesíite 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 zálesíite?+

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

What minerals are found with zálesíite?+

Zálesíite commonly co-occurs with Arsenopyrite, Erythrite, Conichalcite, Malachite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does zálesíite form in?+

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

What is zálesíite used for?+

Zálesíite is used in collector.

Find zálesíite on the map

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