Chlorite Schist
“Soft, green, and foliated”
Chlorite schist is a green, foliated metamorphic rock dominated by the mineral chlorite, formed under relatively low-grade metamorphic conditions. Its softness, slippery feel, and tendency to form along fault zones have given it a reputation among engineers as a problematic rock for construction.
chlorite, quartz, albite, epidote, actinolite, magnetite
Vermont (USA), Scottish Highlands, Alps, Appalachian Mountains, Scandinavian Caledonides
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Chlorite schist's slippery nature has caused numerous landslides and tunnel collapses throughout history — it's one of the rocks that geotechnical engineers dread encountering.
Test Your Knowledge
Why does chlorite schist frequently cause engineering problems in tunnels and road cuttings?
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