1 Definition
1.1 Definition
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
Trachyte is a grey fine-grained volcanic rock which mainly consists of alkali feldspar
1.2 History
1.2.1 Origin
1.2.2 Discoverer
Unknown
Alexandre Brongniart and René Just Haüy
1.3 Etymology
From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use
From Greek trakhus rough’ or trakhutēs roughness
1.4 Class
Sedimentary Rocks
Igneous Rocks
1.4.1 Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
1.5 Family
1.5.1 Group
1.6 Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock