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, so 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, 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.