Yurmarinite is a very rare sodium iron copper arsenate mineral originally discovered in the Kamchatka Peninsula of Russia. It typically appears as small, yellowish tabular crystals associated with arsenic-rich hydrothermal environments. Due to its extreme scarcity, it is considered a premier locality-specific specimen for advanced collectors.

Hardness

~4.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Yurmarinite

Hardness: ~4.5
Luster: Vitreous
Streak: White
Transparency: Transparent

No image

Is this yurmarinite?

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 yurmarinite with a known reference. Yurmarinite sits at Mohs ~4.5, 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: pale green, pale yellowish green, colorless.
5
Look at form & habit
Crystal system: trigonal. Typical habit: small tabular crystals and crusts.

Often found alongside yurmarinite

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

All properties

Chemical formula: Na₇(Fe,Mg,Cu)₄(AsO₄)₆
Mohs hardness: ~4.5
Density: 4.001 g/cm³
Colors: Pale greenPale yellowish greenColorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Small tabular crystals and crusts
Cleavage: Imperfect, one direction
Rarity: Rare
Uses: Collector
Host rock: Formed as sublimates on basaltic scoria around an active volcanic fumarole

Where rockhounds find yurmarinite

Classic worldwide localities

Arsenatnaya fumarole, Second scoria cone, Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia

Field-hunting tip

Where it forms: Formed as sublimates on basaltic scoria around an active volcanic fumarole. If you start seeing hatertite, bradaczekite, johillerite in float, you are in the right ground. Typical habit: small tabular crystals and crusts. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify yurmarinite?+

Mohs hardness is ~4.5. Luster: vitreous. The streak is white. Common colors include pale green, pale yellowish green, colorless.

Where is yurmarinite found?+

Notable localities include Arsenatnaya fumarole, Second scoria cone, Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia.

Is yurmarinite safe to handle?+

Yurmarinite contains arsenic and copper and calls for real care. Contains arsenic, which is toxic; avoid inhalation of dust, ingestion, or skin contact. Wash hands thoroughly after handling specimens.

What minerals are found with yurmarinite?+

Yurmarinite commonly co-occurs with Hatertite, Bradaczekite, Johillerite, Hematite, Tenorite, Tilasite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does yurmarinite form in?+

Where it forms: Formed as sublimates on basaltic scoria around an active volcanic fumarole. Working float back to the host body is the standard way to chase a fresh occurrence.

What is yurmarinite used for?+

Yurmarinite is used in collector.

Find yurmarinite on the map

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