Definition
Greywacke is defined as a dark coarse-grained sandstone rock which contains more than 15 per cent clay
Marble is a non-foliated metamorphic rock which is composed of recrystallized carbonate which is formed when limestone is exposed to high temperatures and pressures over a long time
History
Origin
-
Egypt
Discoverer
Unknown
Unknown
Etymology
From German Grauwacke, from grau grey + wacke
From the Greek marmaros, shining stone and also from the English word marmoreal meaning marble-like
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
-
Other Categories
Fine Grained Rock, Opaque Rock
Medium Grained Rock, Opaque Rock