Itelmenite is a rare copper-bearing sulfate mineral found in volcanic fumaroles. It typically appears as small, tabular monoclinic crystals and is primarily a scientific curiosity for advanced mineral collectors.

Hardness

2-3

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Itelmenite

Hardness: 2-3
Luster: Vitreous
Streak: White
Transparency: Transparent

No image

Is this itelmenite?

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 itelmenite with a known reference. Itelmenite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: light grayish blue.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals.

Often confused with

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

mineral

Fedotovite

Mohs 2.5

How to tell apart: Streak differs, so Itelmenite leaves white, Fedotovite leaves pale grass-green.

How to tell apart: Streak differs, so Itelmenite leaves white, Kamchatkite leaves yellow.

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Often found alongside itelmenite

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

All properties

Chemical formula: Na₂CuMg₂(SO₄)₄
Mohs hardness: 2-3
Density: 3.10 g/cm³
Colors: Light grayish blue
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: As sublimates on basaltic scoria near a volcanic fumarole vent (~600-610 °C.)

Where rockhounds find itelmenite

Classic worldwide localities

Saranchinaitovaya fumarole, Naboko scoria cone, Tolbachik volcano, Kamchatka Peninsula, Russia

Field-hunting tip

Where it forms: As sublimates on basaltic scoria near a volcanic fumarole vent (~600-610 °C.). If you start seeing anhydrite, saranchinaite, hermannjahnite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify itelmenite?+

Mohs hardness is 2-3. Luster: vitreous. The streak is white. Common colors include light grayish blue.

Where is itelmenite found?+

Notable localities include Saranchinaitovaya fumarole, Naboko scoria cone, Tolbachik volcano, Kamchatka Peninsula, Russia.

Is itelmenite safe to handle?+

Itelmenite contains copper. Contains copper; handle with care and wash hands after handling to avoid ingestion or skin irritation.

What rocks look like itelmenite?+

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

What minerals are found with itelmenite?+

Itelmenite commonly co-occurs with Anhydrite, Saranchinaite, Hermannjahnite, Euchlorine, Thénardite, Aphthitalite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does itelmenite form in?+

Where it forms: As sublimates on basaltic scoria near a volcanic fumarole vent (~600-610 °C.). Working float back to the host body is the standard way to chase a fresh occurrence.

What is itelmenite used for?+

Itelmenite is used in collector.

Find itelmenite on the map

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