Hansblockite is a very rare selenium-bearing mineral typically found as small grains within hydrothermal ore deposits. Collectors primarily find this mineral in advanced mineral suites alongside other rare selenides, often requiring professional analysis for positive identification.

Hardness

2-2.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrareCobaltite Group family

Hansblockite

Hardness: 2-2.5
Luster: Metallic
Streak: Black
Transparency: Opaque

No image

Is this hansblockite?

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 hansblockite with a known reference. Hansblockite sits at Mohs 2-2.5, 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: black, cream.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: anhedral grains.

Often confused with

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

mineral

Clausthalite

Mohs 2.5-3

How to tell apart: Streak differs, so Hansblockite leaves black, Clausthalite leaves grayish black.

How to tell apart: Streak differs, so Hansblockite leaves black, Tiemannite leaves nearly black.

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Often found alongside hansblockite

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

All properties

Chemical formula: (Cu,Hg)(Bi,Pb)Se₂
Mohs hardness: 2-2.5
Density: 8.26 g/cm³
Colors: Black Cream
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Anhedral grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In a vein cutting interbedded pyritiferous black shales and hematite-bearing siltstones

Where rockhounds find hansblockite

Classic worldwide localities

El Dragόn mine, Province of Antonio Quijarro, Department of Potosí, Bolivia

Field-hunting tip

Where it forms: In a vein cutting interbedded pyritiferous black shales and hematite-bearing siltstones. If you start seeing watkinsonite, clausthalite, eldragónite 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 hansblockite?+

Mohs hardness is 2-2.5. Luster: metallic. The streak is black. Common colors include black, cream.

Where is hansblockite found?+

Notable localities include El Dragόn mine, Province of Antonio Quijarro, Department of Potosí, Bolivia.

Is hansblockite safe to handle?+

Hansblockite contains copper, lead, mercury and selenium and calls for real care. Contains selenium; handle with care and avoid inhalation of dust or ingestion. Wash hands thoroughly after handling.

What rocks look like hansblockite?+

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

What minerals are found with hansblockite?+

Hansblockite commonly co-occurs with Watkinsonite, Clausthalite, Eldragónite, Krut’aite-penroseite solid solution, Eskebornite, Klockmannite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does hansblockite form in?+

Where it forms: In a vein cutting interbedded pyritiferous black shales and hematite-bearing siltstones. Working float back to the host body is the standard way to chase a fresh occurrence.

What is hansblockite used for?+

Hansblockite is used in collector.

Find hansblockite on the map

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