Coldwellite is a rare palladium-antimony mineral primarily identified from the Coldwell Complex in Ontario. It typically occurs as microscopic anhedral grains associated with other base-metal sulfides and platinum-group minerals in alkaline igneous rocks.

Hardness

3-4

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Coldwellite

Hardness: 3-4
Luster: Metallic
Streak: Black
Transparency: Opaque

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Is this coldwellite?

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 coldwellite with a known reference. Coldwellite sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Coldwellite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Coldwellite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: white, pale yellow.
5
Look at form & habit
Crystal system: cubic. Typical habit: anhedral grains.

Often confused with

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

How to tell apart: Geversite is the harder of the two (Mohs 5.5 vs. 3-4).

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Often found alongside coldwellite

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

All properties

Chemical formula: Pd₃Sb
Mohs hardness: 3-4
Density: 9.52 g/cm³
Colors: White Pale Yellow
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Anhedral Grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Alkaline Igneous Complex

Where rockhounds find coldwellite

Classic worldwide localities

Coldwell Complex, Ontario, Canada

Field-hunting tip

Look in alkaline igneous complex country, the host setting where coldwellite typically forms. If you start seeing chalcopyrite, magnetite, ilmenite in float, you are in the right ground. Field specimens usually show a anhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify coldwellite?+

Mohs hardness is 3-4. It typically shows a metallic luster. The streak is black. Common colors include white, pale yellow.

Where is coldwellite found?+

Notable localities include Coldwell Complex, Ontario, Canada.

Is coldwellite safe to handle?+

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

What rocks look like coldwellite?+

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

What minerals are found with coldwellite?+

Coldwellite commonly co-occurs with Chalcopyrite, Magnetite, Ilmenite, Bornite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does coldwellite form in?+

Coldwellite typically forms in alkaline igneous complex. Working float back to the host body is the standard way to chase a fresh occurrence.

What is coldwellite used for?+

Coldwellite is used in collector.

Find coldwellite on the map

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