Aleksite is a rare lead bismuth telluride-sulfide that typically forms as foliated, metallic-gray aggregates. Collectors usually find it as a minor constituent within hydrothermal gold-telluride vein systems, often intergrown with other bismuth tellurides.

Hardness

1.5-2

Mohs

Luster

Metallic

Streak

Gray

Transparency

Opaque

mineralrareTetradymite Group family

Aleksite

Hardness: 1.5-2
Luster: Metallic
Streak: Gray
Transparency: Opaque

Is this aleksite?

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 aleksite with a known reference. Aleksite sits at Mohs 1.5-2 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Aleksite leaves a gray streak.
3
Read the luster
Hold the specimen under a strong light. Aleksite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: white, lead-gray.
5
Look at form & habit
Crystal system: trigonal. Typical habit: lamellar to foliated masses.

Often confused with

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

mineral

Tetradymite

Mohs 1.5-2

How to tell apart: Streak differs — Aleksite leaves gray, Tetradymite leaves lead-gray.

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

Compare →

Often found alongside aleksite

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

All properties

Chemical formula: PbBi₂Te₂S₂
Mohs hardness: 1.5-2
Density: 8.3 g/cm³
Colors: White Lead-gray
Streak: Gray
Luster: Metallic
Transparency: Opaque
Crystal system: Trigonal
Crystal habit: Lamellar to Foliated Masses
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Gold-telluride Deposits
Typical price: $50-300 per specimen

Where rockhounds find aleksite

Classic worldwide localities

Aleksodskoje deposit (Russia)
Moctezuma mine (Mexico)
Sandaowanzi mine (China)

Field-hunting tip

Look in hydrothermal gold-telluride deposits country — that is the host setting where aleksite typically forms. If you start seeing gold, quartz, pyrite in float, you are in the right ground. Field specimens usually show a lamellar to foliated masses habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify aleksite?+

Mohs hardness is 1.5-2. It typically shows a metallic luster. The streak is gray. Common colors include white, lead-gray.

Where is aleksite found?+

Notable localities include Aleksodskoje deposit (Russia); Moctezuma mine (Mexico); Sandaowanzi mine (China).

How much is aleksite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is aleksite safe to handle?+

It contains toxic constituents. Contains lead and tellurium; handle with care and avoid inhalation of dust or ingestion. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like aleksite?+

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

What minerals are found with aleksite?+

Aleksite commonly co-occurs with Gold, Quartz, Pyrite, Tellurobismuthite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does aleksite form in?+

Aleksite typically forms in hydrothermal gold-telluride deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is aleksite used for?+

Aleksite is used in collector.

Find aleksite on the map

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