Penzhinite is a rare silver-gold-copper sulfosalt mineral primarily identified from epithermal deposits in the Russian Far East. It typically occurs as microscopic anhedral grains intergrown with other precious metal minerals, requiring microscopic analysis for positive identification.

Hardness

2.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrareMiner Group family

Penzhinite

Hardness: 2.5
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this penzhinite?

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 penzhinite with a known reference. Penzhinite sits at Mohs 2.5, 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: gray white, steel gray.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: anhedral grains.

Often confused with

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

How to tell apart: Streak differs, so Penzhinite leaves black, Petrovskaite leaves dark gray; luster reads metallic on Penzhinite and dull metallic on Petrovskaite.

Often found alongside penzhinite

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

All properties

Chemical formula: (Ag,Cu)₄Au(S,Se)₄
Mohs hardness: 2.5
Density: 8.35 g/cm³
Colors: Gray white Steel gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Hexagonal
Crystal habit: Anhedral grains
Cleavage: None
Rarity: Rare
Uses: Collector, Scientific research
Host rock: In a near-surface Au–Ag deposit

Where rockhounds find penzhinite

Classic worldwide localities

Sergeevskoye Au–Ag deposit, 60 km northeast of Pevirechenskii, near the Penzhina River, northern Kamchatka, Russia (type locality)

Field-hunting tip

Where it forms: In a near-surface Au–Ag deposit. If you start seeing gold, aguilarite, chalcopyrite in float, you are in the right ground. Typical habit: anhedral grains. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify penzhinite?+

Mohs hardness is 2.5. Luster: metallic. The streak is black. Common colors include gray white, steel gray.

Where is penzhinite found?+

Notable localities include Sergeevskoye Au–Ag deposit, 60 km northeast of Pevirechenskii, near the Penzhina River, northern Kamchatka, Russia (type locality).

Is penzhinite safe to handle?+

Penzhinite contains copper and selenium. Contains silver and copper, but specifically significant concentrations of heavy metals; handle with care and wash hands after contact.

What rocks look like penzhinite?+

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

What minerals are found with penzhinite?+

Penzhinite commonly co-occurs with Gold, Aguilarite, Chalcopyrite, Galena. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does penzhinite form in?+

Where it forms: In a near-surface Au–Ag deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is penzhinite used for?+

Penzhinite is used in collector, scientific research.

Find penzhinite on the map

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