Definition
Foidolite is a rare type of coarse-grained intrusive igneous rock with a feldspathoid mineral content greater than 60%
Gritstone or grit is a hard, coarse-grained, siliceous sandstone
History
Origin
-
Pennines, England
Discoverer
Unknown
J.J. Ferber
Etymology
From the mineral feldspathoid which is the main content of rock
From Grit + Stone
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Family
Group
Plutonic
-
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock