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

mineralrare

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, 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.