Kurilite is a rare silver telluride-selenide mineral typically found as microscopic grains within epithermal precious metal veins. It is notoriously difficult to identify without laboratory methods like electron microprobe analysis due to its small size and similarity to other silver tellurides.

Hardness

2.5-3

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Kurilite

Hardness: 2.5-3
Luster: Metallic
Streak: Black
Transparency: Opaque

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Is this kurilite?

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 kurilite with a known reference. Kurilite sits at Mohs 2.5-3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Kurilite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Kurilite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: silver-white, pale brass-yellow.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: anhedral grains, microscopic inclusions.

Often confused with

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

How to tell apart: Streak differs — Kurilite leaves black, Tellurobismuthite leaves lead-gray.

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Often found alongside kurilite

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

All properties

Chemical formula: Ag₈Te₃Se
Mohs hardness: 2.5-3
Density: 8.8-9.0 g/cm³
Colors: Silver-white Pale Brass-yellow
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Hexagonal
Crystal habit: Anhedral Grains, Microscopic Inclusions
Cleavage: None
Rarity: Rare
Uses: Collector, Scientific Research
Host rock: Epithermal Gold-silver Deposits
Typical price: $100-500+ for micro-specimens

Where rockhounds find kurilite

Classic worldwide localities

Kuril Islands, Russia
Hokkaido, Japan

Field-hunting tip

Look in epithermal gold-silver deposits country — that is the host setting where kurilite typically forms. If you start seeing gold, silver, tellurium in float, you are in the right ground. Field specimens usually show a anhedral grains, microscopic inclusions habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify kurilite?+

Mohs hardness is 2.5-3. It typically shows a metallic luster. The streak is black. Common colors include silver-white, pale brass-yellow.

Where is kurilite found?+

Notable localities include Kuril Islands, Russia; Hokkaido, Japan.

How much is kurilite worth?+

Typical asking prices fall in the range of $100-500+ for micro-specimens. Quality, size, and provenance can move individual specimens well outside that range.

Is kurilite safe to handle?+

It contains toxic constituents. Contains silver and selenium; handle with care to avoid ingestion or inhalation of dust. Wash hands thoroughly after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like kurilite?+

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

What minerals are found with kurilite?+

Kurilite commonly co-occurs with Gold, Silver, Tellurium, Petzite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kurilite form in?+

Kurilite typically forms in epithermal gold-silver deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is kurilite used for?+

Kurilite is used in collector, scientific research.

Find kurilite on the map

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