Definition
Greywacke is defined as a dark coarse-grained sandstone rock which contains more than 15 per cent clay
Pyrolite is an igneous rock consisting of about three parts of peridotite and one part of basalt
History
Origin
-
Pike County, U.S
Discoverer
Unknown
Unknown
Etymology
From German Grauwacke, from grau grey + wacke
From the chemical and mineralogical composition of the upper mantle of the Earth
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
Plutonic
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock