Siegenite is a member of the linnaeite group typically found as metallic, steel-gray octahedral crystals or massive granular aggregates. It is most commonly identified by its association with other base metal sulfides in hydrothermal deposits and is a notable indicator mineral for nickel-cobalt mineralization.

Hardness

4.5-5.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineraluncommonLinnaeite Group family

Siegenite

Hardness: 4.5-5.5
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this siegenite?

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 siegenite with a known reference. Siegenite sits at Mohs 4.5-5.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Siegenite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Siegenite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: steel gray, silver white, light gray.
5
Look at form & habit
Crystal system: cubic. Typical habit: octahedral crystals, massive, granular.

Often confused with

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

How to tell apart: Streak differs — Siegenite leaves black, Pentlandite leaves light bronze-brown.

Often found alongside siegenite

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

All properties

Chemical formula: (Ni,Co)₃S₄
Mohs hardness: 4.5-5.5
Density: 4.6-4.9 g/cm³
Colors: Steel Gray Silver White Light Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Octahedral Crystals, Massive, Granular
Cleavage: None
Rarity: Uncommon
Uses: Collector, Ore of Nickel
Host rock: Hydrothermal Veins, Nickel-cobalt Sulfide Deposits
Typical price: $15-80 for small specimens

Where rockhounds find siegenite

Classic worldwide localities

Siegen, Germany
Fredericktown, Missouri, USA
Shaba, DR Congo
Sudbury, Ontario, Canada

Field-hunting tip

Look in hydrothermal veins, nickel-cobalt sulfide deposits country — that is the host setting where siegenite typically forms. If you start seeing chalcopyrite, galena, sphalerite in float, you are in the right ground. Field specimens usually show a octahedral crystals, massive, granular habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify siegenite?+

Mohs hardness is 4.5-5.5. It typically shows a metallic luster. The streak is black. Common colors include steel gray, silver white, light gray.

Where is siegenite found?+

Notable localities include Siegen, Germany; Fredericktown, Missouri, USA; Shaba, DR Congo; Sudbury, Ontario, Canada.

How much is siegenite worth?+

Typical asking prices fall in the range of $15-80 for small specimens. Quality, size, and provenance can move individual specimens well outside that range.

Is siegenite safe to handle?+

It contains toxic constituents. Contains nickel and cobalt; wash hands thoroughly after handling to prevent ingestion or skin irritation, and avoid creating dust when grinding or breaking. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like siegenite?+

Siegenite is most often confused with Linnaeite, Pentlandite, Carrollite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with siegenite?+

Siegenite commonly co-occurs with Chalcopyrite, Galena, Sphalerite, Pyrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does siegenite form in?+

Siegenite typically forms in hydrothermal veins, nickel-cobalt sulfide deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is siegenite used for?+

Siegenite is used in collector, ore of nickel.

Find siegenite on the map

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