Crerarite is an extremely rare platinum-group mineral found as tiny inclusions or irregular aggregates within massive sulfides. It is primarily identified through electron microprobe analysis given its microscopic habit and similarity to other opaque metallic minerals.

Hardness

3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Crerarite

Hardness: 3.5
Luster: Metallic
Streak: Black
Transparency: Opaque

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Is this crerarite?

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 crerarite with a known reference. Crerarite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Crerarite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Crerarite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: black.
5
Look at form & habit
Crystal system: cubic. Typical habit: microcrystalline aggregates.

Often confused with

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

mineral

Sperrylite

Mohs 6-7

How to tell apart: Sperrylite is the harder of the two (Mohs 6-7 vs. 3.5).

How to tell apart: Crerarite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs — Crerarite leaves black, Galena leaves lead-gray.

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Often found alongside crerarite

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

All properties

Chemical formula: (Pt,Pb)Bi₃(S,Se)₄
Mohs hardness: 3.5
Density: 9.43 g/cm³
Colors: Black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Microcrystalline Aggregates
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Platinum-group Mineral Deposits
Typical price: n/a

Where rockhounds find crerarite

Classic worldwide localities

Crerar Mine, Ontario, Canada

Field-hunting tip

Look in hydrothermal platinum-group mineral deposits country — that is the host setting where crerarite typically forms. If you start seeing sperrylite, chalcopyrite, pyrrhotite in float, you are in the right ground. Field specimens usually show a microcrystalline aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify crerarite?+

Mohs hardness is 3.5. It typically shows a metallic luster. The streak is black. Common colors include black.

Where is crerarite found?+

Notable localities include Crerar Mine, Ontario, Canada.

How much is crerarite worth?+

Typical asking prices fall in the range of n/a. Quality, size, and provenance can move individual specimens well outside that range.

Is crerarite safe to handle?+

It contains toxic constituents. Contains lead (Pb); wash hands thoroughly after handling and avoid ingestion or inhalation of dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like crerarite?+

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

What minerals are found with crerarite?+

Crerarite commonly co-occurs with Sperrylite, Chalcopyrite, Pyrrhotite, Galena. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does crerarite form in?+

Crerarite typically forms in hydrothermal platinum-group mineral deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is crerarite used for?+

Crerarite is used in collector.

Find crerarite on the map

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