Hornfels
“Baked by magma's touch”
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.
variable — andalusite, cordierite, biotite, quartz, pyroxene
Dartmoor (England), Oslo (Norway), Sierra Nevada (USA), Harz Mountains (Germany)
6-7
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
Cordierite Hornfels
“Baked to hardness by magma's heat”
Cornubianite
“Ultra-high temperature contact hornfels”
Metapelite (Sillimanite Zone)
“Mud transformed at the highest metamorphic grade”
Cordierite-Anthophyllite Rock
“Metamorphosed from chemically exotic protoliths”
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