Definition
Origin
Discoverer
Etymology
Class
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Other Categories
Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation
From French schiste, Greek skhistos i.e. split
Durable Rock, Medium Hardness Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Trachyte is a grey fine-grained volcanic rock which mainly consists of alkali feldspar
Alexandre Brongniart and René Just Haüy
From Greek trakhus rough’ or trakhutēs roughness
Durable Rock, Medium Hardness Rock
Fine Grained Rock, Opaque Rock