Definition
Arkose is a sedimentary rock, specifically a type of sandstone containing at least 25% feldspar
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
Discoverer
Alexandre Brongniart
Van Tooren
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 tephra, ashes from Indo-European base, to burn
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock