Tredouxite is a rare nickel antimony oxide, typically black. It occurs in a podiform nickeliferous deposit in altered ultramafic rocks. It is associated with trevorite and bottinoite. It was first described from Bon Accord Ni-oxide deposit, southeast of Nelspruit, Republic of South Africa.

Hardness

3-3.5

Mohs

Luster

Submetallic

Streak

Gray

Transparency

Opaque

mineralrare

Tredouxite

Hardness: 3-3.5
Luster: Submetallic
Streak: Gray
Transparency: Opaque

No image

Is this tredouxite?

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 tredouxite with a known reference. Tredouxite sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Tredouxite leaves a gray streak.
3
Read the luster
Hold the specimen under a strong light. Tredouxite typically shows a submetallic luster.
4
Match the color range
Compare against the expected color range: black.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: anhedral grains.

Often confused with

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

How to tell apart: Manaccanite is the harder of the two (Mohs 5-6 vs. 3-3.5); streak differs, so Tredouxite leaves gray, Manaccanite leaves black.

How to tell apart: Magnetite is the harder of the two (Mohs 5.5-6.5 vs. 3-3.5); streak differs, so Tredouxite leaves gray, Magnetite leaves black; luster reads submetallic on Tredouxite and metallic to submetallic to dull on Magnetite.

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Often found alongside tredouxite

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

All properties

Chemical formula: NiSb₂O₆
Mohs hardness: 3-3.5
Density: 6.650 g/cm³
Colors: Black
Streak: Gray
Luster: Submetallic
Transparency: Opaque
Crystal system: Tetragonal
Crystal habit: Anhedral Grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Ultramafic Rocks

Where rockhounds find tredouxite

Classic worldwide localities

Bon Accord nickel deposit, South Africa

Field-hunting tip

Look in ultramafic rocks country, the host setting where tredouxite typically forms. If you start seeing trevorite, willemseite, bunsenite 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 tredouxite?+

Mohs hardness is 3-3.5. It typically shows a submetallic luster. The streak is gray. Common colors include black.

Where is tredouxite found?+

Notable localities include Bon Accord nickel deposit, South Africa.

Is tredouxite safe to handle?+

It contains toxic constituents. Contains antimony and nickel, which are toxic if ingested or inhaled as dust. Wash hands thoroughly after handling and avoid creating dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like tredouxite?+

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

What minerals are found with tredouxite?+

Tredouxite commonly co-occurs with Trevorite, Willemseite, Bunsenite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tredouxite form in?+

Tredouxite typically forms in ultramafic rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is tredouxite used for?+

Tredouxite is used in collector.

Find tredouxite on the map

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