Dekatriasartorite is a very rare sulfosalt mineral found almost exclusively in the famous Lengenbach Quarry in Switzerland. It occurs as small, lead-gray, striated prismatic crystals and is prized by advanced collectors for its complex crystal structure and rarity within the sartorite homologous series.

Hardness

Mohs

Luster

Metallic

Transparency

Opaque

mineralrareSartorite homologous series family

Dekatriasartorite

Hardness: 3
Luster: Metallic
Transparency: Opaque

Is this dekatriasartorite?

4-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 dekatriasartorite with a known reference. Dekatriasartorite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
2
Read the luster
Hold the specimen under a strong light. Luster: metallic.
3
Match the color range
Compare against the expected color range: lead-gray, black.
4
Look at form & habit
Crystal system: monoclinic. Typical habit: prismatic, striated crystals.

Often confused with

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

How to tell apart: Luster reads metallic on Dekatriasartorite and submetallic on Dufrénoysite.

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Often found alongside dekatriasartorite

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

All properties

Chemical formula: TlPb₅₈As₉₇S₂₀₄
Mohs hardness: 3
Density: 5.45 g/cm³
Colors: Lead-gray Black
Luster: Metallic
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Prismatic, striated crystals
Rarity: Rare
Uses: Collector
Host rock: dolomitic marble

Where rockhounds find dekatriasartorite

Classic worldwide localities

Lengenbach quarry, Binntal, Wallis, Switzerland

Field-hunting tip

Where it forms: dolomitic marble. If you start seeing galena, realgar, orpiment in float, you are in the right ground. Typical habit: prismatic, striated crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify dekatriasartorite?+

Mohs hardness is 3. Luster: metallic. Common colors include lead-gray, black.

Where is dekatriasartorite found?+

Notable localities include Lengenbach quarry, Binntal, Wallis, Switzerland.

Is dekatriasartorite safe to handle?+

Dekatriasartorite contains arsenic, lead and thallium and calls for real care. Contains arsenic and lead; handle with care and wash hands thoroughly after handling. Do not ingest or inhale dust.

What rocks look like dekatriasartorite?+

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

What minerals are found with dekatriasartorite?+

Dekatriasartorite commonly co-occurs with Galena, Realgar, Orpiment, Pyrite, Baumhauerite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does dekatriasartorite form in?+

Where it forms: dolomitic marble. Working float back to the host body is the standard way to chase a fresh occurrence.

What is dekatriasartorite used for?+

Dekatriasartorite is used in collector.

Find dekatriasartorite on the map

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