Selwynite is a chromium-rich variety of muscovite mica typically found in the greenstone belts of Victoria, Australia. It is most easily identified by its distinctive waxy luster and opaque yellow-green coloration caused by significant chromium content.

Hardness

2.5

Mohs

Luster

Waxy

Streak

White

Transparency

Opaque

mineralrarenull family

Selwynite

Hardness: 2.5
Luster: Waxy
Streak: White
Transparency: Opaque

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Is this selwynite?

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 selwynite with a known reference. Selwynite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Selwynite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Selwynite typically shows a waxy luster.
4
Match the color range
Compare against the expected color range: yellow, green, brown.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: massive.

Often confused with

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

mineral

Fuchsite

Mohs 2.5-3

How to tell apart: Luster reads waxy on Selwynite and pearly on Fuchsite.

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Often found alongside selwynite

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

All properties

Chemical formula: KCr₂(Si₃Al)O₁₀(OH)₂
Mohs hardness: 2.5
Density: 2.7 g/cm³
Colors: Yellow Green Brown
Streak: White
Luster: Waxy
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Massive
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Hydrothermally Altered Greenstone
Typical price: $20-100 for small specimens

Where rockhounds find selwynite

Classic worldwide localities

Heathcote, Victoria, Australia

Field-hunting tip

Look in hydrothermally altered greenstone country — that is the host setting where selwynite typically forms. If you start seeing quartz, chromite, albite in float, you are in the right ground. Field specimens usually show a massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify selwynite?+

Mohs hardness is 2.5. It typically shows a waxy luster. The streak is white. Common colors include yellow, green, brown.

Where is selwynite found?+

Notable localities include Heathcote, Victoria, Australia.

How much is selwynite worth?+

Typical asking prices fall in the range of $20-100 for small specimens. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like selwynite?+

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

What minerals are found with selwynite?+

Selwynite commonly co-occurs with Quartz, Chromite, Albite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does selwynite form in?+

Selwynite typically forms in hydrothermally altered greenstone. Working float back to the host body is the standard way to chase a fresh occurrence.

What is selwynite used for?+

Selwynite is used in collector.

Find selwynite on the map

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