Skarn is a metasomatic rock formed through the interaction of hot hydrothermal fluids with carbonate-rich rocks like limestone or dolostone. Collectors prize skarns for their diverse and often showy mineral assemblages, which frequently include large crystals of garnet, pyroxene, and epidote.

Hardness

5-7

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

metamorphiccommon

Skarn

Hardness: 5-7
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this skarn?

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 skarn with a known reference. Skarn sits at Mohs 5-7, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Skarn leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Skarn typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: green, brown, black, white, red.
5
Look at form & habit
Typical habit: massive.

Often found alongside skarn

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

All properties

Mohs hardness: 5-7
Density: 2.8-3.6 g/cm³
Colors: Green Brown Black White Red
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal habit: Massive
Cleavage: None
Rarity: Common
Uses: Collector, Industrial
Host rock: Metasomatized Carbonate Rocks
Typical price: $5-50 for small specimens, higher for specific mineral associations

Where rockhounds find skarn

Classic worldwide localities

Sweden
USA
Mexico
Russia
China

Field-hunting tip

Look in metasomatized carbonate rocks country, the host setting where skarn typically forms. If you start seeing garnet, pyroxene, epidote 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 skarn?+

Mohs hardness is 5-7. It typically shows a vitreous luster. The streak is white. Common colors include green, brown, black, white.

Where is skarn found?+

Notable localities include Sweden; USA; Mexico; Russia; China.

How much is skarn worth?+

Typical asking prices fall in the range of $5-50 for small specimens, higher for specific mineral associations. Quality, size, and provenance can move individual specimens well outside that range.

What minerals are found with skarn?+

Skarn commonly co-occurs with garnet, pyroxene, epidote, vesuvianite, wollastonite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does skarn form in?+

Skarn typically forms in metasomatized carbonate rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is skarn used for?+

Skarn is used in collector, industrial.

Find skarn on the map

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