Definition
Gritstone or grit is a hard, coarse-grained, siliceous sandstone
Ijolite is an intrusive igneous rock which is composed mainly of nepheline and an alkali pyroxene, usually aegirine-augite
History
Origin
Pennines, England
Finland, Europe
Discoverer
J.J. Ferber
Unknown
Etymology
From Grit + Stone
From the first syllable of the Finnish words Ii-vaara, Iijoki, &c. commonly used geographical names in Finland, and the Gr. Xiflos, a stone
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
Plutonic
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock