Borisenkoite is an extremely rare arsenate mineral discovered in the volcanic fumaroles of the Tolbachik volcano in Russia. It typically appears as dark green to black tabular crystals associated with other secondary copper and iron minerals in high-temperature volcanic environments.

Hardness

Mohs

Luster

Vitreous

Streak

Light Green

Transparency

Translucent

mineralrare

Borisenkoite

Hardness: 4
Luster: Vitreous
Streak: Light Green
Transparency: Translucent

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Is this borisenkoite?

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 borisenkoite with a known reference. Borisenkoite sits at Mohs 4 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Borisenkoite leaves a light green streak.
3
Read the luster
Hold the specimen under a strong light. Borisenkoite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: dark green, black.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals.

Often confused with

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

How to tell apart: Borisenkoite is noticeably harder (Mohs 4 vs. 3); streak differs — Borisenkoite leaves light green, Dolerophanite leaves light red; luster reads vitreous on Borisenkoite and adamantine on Dolerophanite.

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Often found alongside borisenkoite

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

All properties

Chemical formula: Cu₃Fe³⁺₂O₂(AsO₄)₂
Mohs hardness: 4
Density: 3.84 g/cm³
Colors: Dark Green Black
Streak: Light Green
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Fumarolic Deposits
Typical price: n/a

Where rockhounds find borisenkoite

Classic worldwide localities

Tolbachik volcano (Kamchatka, Russia)

Field-hunting tip

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

Common questions

How do you identify borisenkoite?+

Mohs hardness is 4. It typically shows a vitreous luster. The streak is light green. Common colors include dark green, black.

Where is borisenkoite found?+

Notable localities include Tolbachik volcano (Kamchatka, Russia).

How much is borisenkoite worth?+

Typical asking prices fall in the range of n/a. Quality, size, and provenance can move individual specimens well outside that range.

Is borisenkoite safe to handle?+

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

What rocks look like borisenkoite?+

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

What minerals are found with borisenkoite?+

Borisenkoite commonly co-occurs with Lammerite, Dolerophanite, Tenorite, Hematite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does borisenkoite form in?+

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

What is borisenkoite used for?+

Borisenkoite is used in collector.

Find borisenkoite on the map

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