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

Hardness

1.5-2

Mohs

Luster

Vitreous

Streak

Pale green

Transparency

Transparent

mineralrare

Ilinskite

Hardness: 1.5-2
Luster: Vitreous
Streak: Pale green
Transparency: Transparent

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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 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. Streak: pale green.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: emerald green.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: euhedral crystals, tabular.

Often confused with

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

How to tell apart: Streak differs, so Ilinskite leaves pale green, Burnsite leaves red.

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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: 1.5-2
Density: 4.08 g/cm³
Colors: Emerald green
Streak: Pale green
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Euhedral crystals, tabular
Cleavage: {100}, perfect
Rarity: Rare
Uses: Collector
Host rock: A rare volcanic sublimate around fumaroles

Where rockhounds find ilinskite

Classic worldwide localities

Tolbachik fissure volcano, Kamchatka Peninsula, Russia

Field-hunting tip

Where it forms: A rare volcanic sublimate around fumaroles. If you start seeing cotunnite, sofiite, halite in float, you are in the right ground. Typical habit: euhedral crystals, tabular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ilinskite?+

Mohs hardness is 1.5-2. Luster: vitreous. The streak is pale green. Common colors include emerald green.

Where is ilinskite found?+

Notable localities include Tolbachik fissure volcano, Kamchatka Peninsula, Russia.

Is ilinskite safe to handle?+

Ilinskite contains copper and selenium. Contains copper and selenium; handle with care to avoid ingestion or inhalation of dust. Wash hands thoroughly after handling.

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 Cotunnite, Sofiite, Halite, Gold, Tolbachite, Melanothallite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does ilinskite form in?+

Where it forms: A rare volcanic sublimate around fumaroles. 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.