1 Definition
1.1 Definition
Mudstone is a fine-grained, dark gray sedimentary rock, which is formed from silt and clay and is similar to shale but has less laminations
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 the English mud and stone, from low German mudde and stainaz
From Greek trakhus rough’ or trakhutēs roughness
1.4 Class
Sedimentary Rocks
Igneous Rocks
1.4.1 Sub-Class
Durable Rock, Soft 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