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

mineralrare

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, so Uzonite leaves yellow, Realgar leaves orange-red.

How to tell apart: Streak differs, so 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, 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.