Definition
Foidolite is a rare type of coarse-grained intrusive igneous rock with a feldspathoid mineral content greater than 60%
Arkose is a sedimentary rock, specifically a type of sandstone containing at least 25% feldspar
Discoverer
Unknown
Alexandre Brongniart
Etymology
From the mineral feldspathoid which is the main content of rock
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, Soft Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock