Widgiemoolthalite is a rare nickel carbonate mineral that typically forms delicate, radiating sprays of acicular crystals. It is primarily found in the oxidized zones of nickel-rich ore deposits in Western Australia and is highly sought after by systematic mineral collectors.

Hardness

3.5

Mohs

Luster

Silky

Streak

Pale bluish green

Transparency

Semitransparent

mineralrare

Widgiemoolthalite

Hardness: 3.5
Luster: Silky
Streak: Pale bluish green
Transparency: Semitransparent

Is this widgiemoolthalite?

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 widgiemoolthalite with a known reference. Widgiemoolthalite 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. Streak: pale bluish green.
3
Read the luster
Hold the specimen under a strong light. Luster: silky.
4
Match the color range
Compare against the expected color range: blue green, green.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: acicular, massive, spherical.

Often confused with

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

mineral

Hydrotalcite

Mohs 2

How to tell apart: Widgiemoolthalite is noticeably harder (Mohs 3.5 vs. 2); streak differs, so Widgiemoolthalite leaves pale bluish green, Hydrotalcite leaves white; luster reads silky on Widgiemoolthalite and satiny to greasy or waxy on Hydrotalcite.

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Often found alongside widgiemoolthalite

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

Gaspéite
mineral · Mohs 4.5-5

All properties

Chemical formula: Ni₅(CO₃)₄(OH)₂·4-5H₂O
Mohs hardness: 3.5
Density: 3.13 g/cm³
Colors: Blue green Green
Streak: Pale bluish green
Luster: Silky
Transparency: Semitransparent
Crystal system: Monoclinic
Crystal habit: Acicular, massive, spherical
Cleavage: Perfect on {hk0}
Rarity: Rare
Uses: Collector
Host rock: In a stockpile of weathered ore from a hydrothermal nickel deposit

Where rockhounds find widgiemoolthalite

Classic worldwide localities

132 North Nickel mine, 4 km SW of Widgiemooltha, 80 km S of Kalgoorlie, Australia (type locality)

Field-hunting tip

Where it forms: In a stockpile of weathered ore from a hydrothermal nickel deposit. If you start seeing gaspéite in float, you are in the right ground. Typical habit: acicular, massive, spherical. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify widgiemoolthalite?+

Mohs hardness is 3.5. Luster: silky. The streak is pale bluish green. Common colors include blue green, green.

Where is widgiemoolthalite found?+

Notable localities include 132 North Nickel mine, 4 km SW of Widgiemooltha, 80 km S of Kalgoorlie, Australia (type locality).

Is widgiemoolthalite safe to handle?+

Widgiemoolthalite contains nickel. Contains nickel, which is a skin irritant and potential carcinogen. Wash hands thoroughly after handling and avoid inhaling dust.

What rocks look like widgiemoolthalite?+

Widgiemoolthalite is most often confused with Hydrotalcite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with widgiemoolthalite?+

Widgiemoolthalite commonly co-occurs with Gaspéite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does widgiemoolthalite form in?+

Where it forms: In a stockpile of weathered ore from a hydrothermal nickel deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is widgiemoolthalite used for?+

Widgiemoolthalite is used in collector.

Find widgiemoolthalite on the map

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