Definition
Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
History
Origin
-
Germany
Discoverer
Unknown
Van Tooren
Etymology
From French schiste, Greek skhistos i.e. split
From Greek tephra, ashes from Indo-European base, to burn
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
-
Volcanic
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock