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 — that is 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.