Definition
Greywacke is defined as a dark coarse-grained sandstone rock which contains more than 15 per cent clay
An iron rich extrusive rock found as a member of the alkali basalt magma series
History
Origin
-
Isle of Mull, Scotland
Discoverer
Unknown
Ben More
Etymology
From German Grauwacke, from grau grey + wacke
From the name of discoverer, Ben More
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock