Definition
Arkose is a sedimentary rock, specifically a type of sandstone containing at least 25% feldspar
Trachyte is a grey fine-grained volcanic rock which mainly consists of alkali feldspar
History
Origin
France
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Discoverer
Alexandre Brongniart
Alexandre Brongniart and René Just Haüy
Etymology
From Auvergne region of France used by a French geologist Alexandre Brongniart in 1826 who applied this term to some feldspathic sandstones
From Greek trakhus rough’ or trakhutēs roughness
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
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Volcanic
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock