Definition
Phonolite is an uncommon extrusive igneous rock volcanic rock of intermediate chemical composition between felsic and mafic
Gritstone or grit is a hard, coarse-grained, siliceous sandstone
History
Origin
-
Pennines, England
Discoverer
Unknown
J.J. Ferber
Etymology
From the Greek meaning sounding stone because of the metallic sound it produces if an unfractured plate is hit
From Grit + Stone
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
-
-
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock