Definition
Shoshonite is a basaltic rock, properly a potassic trachyandesite, composed of olivine, augite and plagioclase phenocrysts in a groundmass with calcic plagioclase and sanidine and some dark-colored volcanic glass
Gritstone or grit is a hard, coarse-grained, siliceous sandstone
History
Origin
Wyoming,USA
Pennines, England
Discoverer
Iddings
J.J. Ferber
Etymology
From the place of origin called Shoshone riverin Wyoming
From Grit + Stone
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
Volcanic
-
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock