Definition
Andesite is a dark, fine-grained, brown or greyish intermediate volcanic rock which is a commonly found in lava
Arkose is a sedimentary rock, specifically a type of sandstone containing at least 25% feldspar
History
Origin
North America
France
Discoverer
Theodor von Gümbel
Alexandre Brongniart
Etymology
From Andes mountains, where it is found in abundance
From Auvergne region of France used by a French geologist Alexandre Brongniart in 1826 who applied this term to some feldspathic sandstones
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Family
Group
Volcanic
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Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock