Hornfels
“Baked by magma's touch”
Metamorphic
Hornfels is a fine-grained, hard metamorphic rock formed by contact metamorphism — when existing rocks are baked by the heat of an intruding magma body without significant pressure. The result is a tough, dense, often splintery rock.
Composition
variable — andalusite, cordierite, biotite, quartz, pyroxene
Where Found
Dartmoor (England), Oslo (Norway), Sierra Nevada (USA), Harz Mountains (Germany)
Mohs Hardness
6-7
Fun Fact
The name 'hornfels' comes from German, meaning 'horn rock,' because the rock is so tough it breaks like animal horn.
Test Your Knowledge
Why does hornfels lack the foliation (layered texture) seen in schist and gneiss?
Related Specimens
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