Ilinskite is a rare volcanic mineral found exclusively in the fumaroles of the Tolbachik volcano in Russia. It typically appears as distinct, bright yellow to orange tabular crystals or crusts that form in high-temperature volcanic environments.

Hardness

Mohs

Luster

Vitreous

Streak

Yellow

Transparency

Translucent

mineralrare

Ilinskite

Hardness: 3
Luster: Vitreous
Streak: Yellow
Transparency: Translucent

No image

Is this ilinskite?

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 ilinskite with a known reference. Ilinskite 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. Ilinskite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Ilinskite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: yellow, orange, brown.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals, crusts, aggregates.

Often confused with

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

How to tell apart: Streak differs — Ilinskite leaves yellow, Burnsite leaves white.

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Often found alongside ilinskite

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

All properties

Chemical formula: NaCu₅O₂(SeO₃)₂Cl₃
Mohs hardness: 3
Density: 3.31 g/cm³
Colors: Yellow Orange Brown
Streak: Yellow
Luster: Vitreous
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Tabular Crystals, Crusts, Aggregates
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Fumarole Deposits
Typical price: $100-500+ for thumbnail specimens

Where rockhounds find ilinskite

Classic worldwide localities

Tolbachik volcano, Kamchatka, Russia

Field-hunting tip

Look in fumarole deposits country — that is the host setting where ilinskite typically forms. If you start seeing sophiite, burnsite, tenorite in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts, aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ilinskite?+

Mohs hardness is 3. It typically shows a vitreous luster. The streak is yellow. Common colors include yellow, orange, brown.

Where is ilinskite found?+

Notable localities include Tolbachik volcano, Kamchatka, Russia.

How much is ilinskite worth?+

Typical asking prices fall in the range of $100-500+ for thumbnail specimens. Quality, size, and provenance can move individual specimens well outside that range.

Is ilinskite safe to handle?+

It contains toxic constituents. Contains copper and selenium; handle with care to avoid ingestion or inhalation of dust. Wash hands thoroughly after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like ilinskite?+

Ilinskite is most often confused with Burnsite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with ilinskite?+

Ilinskite commonly co-occurs with sophiite, burnsite, tenorite, halite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does ilinskite form in?+

Ilinskite typically forms in fumarole deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is ilinskite used for?+

Ilinskite is used in collector.

Find ilinskite on the map

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