Definition
Greywacke is defined as a dark coarse-grained sandstone rock which contains more than 15 per cent clay
It is a metamorphic magnesium rich rock because it is composed of the mineral talc
History
Origin
-
USA
Discoverer
Unknown
Unknown
Etymology
From German Grauwacke, from grau grey + wacke
From 17th century, because of its greasy feel and use like a soap
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Family
Group
-
-
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock