Definition
Arkose is a sedimentary rock, specifically a type of sandstone containing at least 25% feldspar
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
History
Origin
France
Italy
Discoverer
Alexandre Brongniart
Unknown
Etymology
From Auvergne region of France used by a French geologist Alexandre Brongniart in 1826 who applied this term to some feldspathic sandstones
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Family
Group
-
Volcanic
Other Categories
Coarse Grained Rock, Opaque Rock
Medium Grained Rock, Opaque Rock