1 Definition
1.1 Definition
Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles
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 German Schalstein laminated limestone, and Schalgebirge layer of stone in stratified rock. From Old English scealu in its base sense of- thing that divides or separate,
From Greek trakhus rough’ or trakhutēs roughness
1.4 Class
Sedimentary Rocks
Igneous Rocks
1.4.1 Sub-Class
Durable Rock, Medium Hardness 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