Murunskite is a rare potassium-copper-iron sulfide mineral first discovered in the Murun Massif in Siberia. Collectors typically find it as microscopic inclusions or small massive grains within alkaline rock environments rather than as well-formed macro crystals.

Hardness

3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Murunskite

Hardness: 3.5
Luster: Metallic
Streak: Black
Transparency: Opaque

No image

Is this murunskite?

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 murunskite with a known reference. Murunskite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: black.
3
Read the luster
Hold the specimen under a strong light. Luster: metallic.
4
Match the color range
Compare against the expected color range: blue gray, copper brown, black.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: aggregates, granular.

Often confused with

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

mineral

Bornite

Mohs 3-3.25

How to tell apart: Streak differs, so Murunskite leaves black, Bornite leaves pale grayish black.

How to tell apart: Streak differs, so Murunskite leaves black, Chalcopyrite leaves greenish black.

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Often found alongside murunskite

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

All properties

Chemical formula: K₂Cu₃FeS₄
Mohs hardness: 3.5
Density: 3.86 g/cm³
Colors: Blue grayCopper brownBlack
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Tetragonal
Crystal habit: Aggregates, granular
Cleavage: Imperfect
Rarity: Rare
Uses: Collector, Scientific research
Host rock: In rocks that have undergone intensive potassium metasomatism

Where rockhounds find murunskite

Classic worldwide localities

Murun alkalic massif, near Olekminsk, Sakha and Mt. Koashva, Khibiny massif, Kola Peninsula, Russia

Field-hunting tip

Where it forms: In rocks that have undergone intensive potassium metasomatism. If you start seeing charoite, acmite, potassium feldspar in float, you are in the right ground. Typical habit: aggregates, granular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify murunskite?+

Mohs hardness is 3.5. Luster: metallic. The streak is black. Common colors include blue gray, copper brown, black.

Where is murunskite found?+

Notable localities include Murun alkalic massif, near Olekminsk, Sakha and Mt. Koashva, Khibiny massif, Kola Peninsula, Russia.

Is murunskite safe to handle?+

Murunskite contains copper. Contains copper and potentially harmful sulfides. Wash hands thoroughly after handling and avoid inhaling dust.

What rocks look like murunskite?+

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

What minerals are found with murunskite?+

Murunskite commonly co-occurs with Charoite, Acmite, Potassium feldspar. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does murunskite form in?+

Where it forms: In rocks that have undergone intensive potassium metasomatism. Working float back to the host body is the standard way to chase a fresh occurrence.

What is murunskite used for?+

Murunskite is used in collector, scientific research.

Find murunskite on the map

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