Definition
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
History
Origin
-
Germany
Discoverer
Unknown
Van Tooren
Etymology
From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use
From Greek tephra, ashes from Indo-European base, to burn
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Family
Group
-
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock