Uzonite is an extremely rare arsenic sulfide mineral found primarily as a product of hot spring activity in volcanic regions. It typically appears as yellow to orange crusts or tiny needle-like crystals and is chemically similar to realgar but crystallizes in a distinct monoclinic form.

Hardness

1.5-2

Mohs

Luster

Resinous

Streak

Yellow

Transparency

Translucent

mineralrarenull family

Uzonite

Hardness: 1.5-2
Luster: Resinous
Streak: Yellow
Transparency: Translucent

Is this uzonite?

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 uzonite with a known reference. Uzonite sits at Mohs 1.5-2 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Uzonite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Uzonite typically shows a resinous luster.
4
Match the color range
Compare against the expected color range: yellow, orange.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: crusts, acicular aggregates.

Often confused with

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

mineral

Realgar

Mohs 1.5-2

How to tell apart: Streak differs — Uzonite leaves yellow, Realgar leaves orange-red.

How to tell apart: Streak differs — Uzonite leaves yellow, Pararealgar leaves orange-yellow.

Compare →

Often found alongside uzonite

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

All properties

Chemical formula: As₄S₄
Mohs hardness: 1.5-2
Density: 3.51 g/cm³
Colors: Yellow Orange
Streak: Yellow
Luster: Resinous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Crusts, Acicular Aggregates
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Vents
Typical price: $50-300 per specimen

Where rockhounds find uzonite

Classic worldwide localities

Uzon Caldera, Kamchatka Peninsula, Russia

Field-hunting tip

Look in hydrothermal vents country — that is the host setting where uzonite typically forms. If you start seeing realgar, sulfur, arsenopyrite in float, you are in the right ground. Field specimens usually show a crusts, acicular aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify uzonite?+

Mohs hardness is 1.5-2. It typically shows a resinous luster. The streak is yellow. Common colors include yellow, orange.

Where is uzonite found?+

Notable localities include Uzon Caldera, Kamchatka Peninsula, Russia.

How much is uzonite 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 uzonite safe to handle?+

It contains toxic constituents. Contains arsenic, which is highly toxic if ingested or inhaled as dust. Wash hands thoroughly after handling and keep in a sealed container. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like uzonite?+

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

What minerals are found with uzonite?+

Uzonite commonly co-occurs with Realgar, Sulfur, Arsenopyrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does uzonite form in?+

Uzonite typically forms in hydrothermal vents. Working float back to the host body is the standard way to chase a fresh occurrence.

What is uzonite used for?+

Uzonite is used in collector.

Find uzonite on the map

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