Kudriavite is an extremely rare cadmium-lead bismuth sulfide mineral found in volcanic fumaroles. It typically forms as small, yellowish, metallic platy crystals occurring within the mineralized vents of high-temperature volcanoes.

Hardness

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Kudriavite

Hardness: 2
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this kudriavite?

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 kudriavite with a known reference. Kudriavite sits at Mohs 2, 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: dark reddish gray.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy.

Often confused with

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

mineral

Galena

Mohs 2.5-2.75

How to tell apart: Streak differs, so Kudriavite leaves black, Galena leaves lead-gray.

How to tell apart: Streak differs, so Kudriavite leaves black, Bismuthinite leaves lead-gray.

Compare →

Often found alongside kudriavite

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

All properties

Chemical formula: (Cd,Pb)Bi₂S₄
Mohs hardness: 2
Density: 6.578 g/cm³
Colors: Dark reddish gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Platy
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: As high-temperature (~ 400 °C) fumarole encrustations on the inner wall of an active andesitic stratovolcanic crater

Where rockhounds find kudriavite

Classic worldwide localities

Kudriavy volcano, Iturup Island, Kurile arc, Russia

Field-hunting tip

Where it forms: As high-temperature (~ 400 °C) fumarole encrustations on the inner wall of an active andesitic stratovolcanic crater. If you start seeing cannizzarite, greenockite, pyrite in float, you are in the right ground. Typical habit: platy. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify kudriavite?+

Mohs hardness is 2. Luster: metallic. The streak is black. Common colors include dark reddish gray.

Where is kudriavite found?+

Notable localities include Kudriavy volcano, Iturup Island, Kurile arc, Russia.

Is kudriavite safe to handle?+

Kudriavite contains cadmium and lead and calls for real care. Contains bismuth, cadmium and lead, which are toxic if ingested or inhaled as dust. Wash hands thoroughly after handling and avoid creating dust.

What rocks look like kudriavite?+

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

What minerals are found with kudriavite?+

Kudriavite commonly co-occurs with Cannizzarite, Greenockite, Pyrite, Sulfur. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kudriavite form in?+

Where it forms: As high-temperature (~ 400 °C) fumarole encrustations on the inner wall of an active andesitic stratovolcanic crater. Working float back to the host body is the standard way to chase a fresh occurrence.

What is kudriavite used for?+

Kudriavite is used in collector.

Find kudriavite on the map

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