Definition
Greywacke is defined as a dark coarse-grained sandstone rock which contains more than 15 per cent clay
Jasperoid is a rare, peculiar type of metasomatic alteration of rocks
History
Origin
-
USA
Discoverer
Unknown
Unknown
Etymology
From German Grauwacke, from grau grey + wacke
From silica, the main mineral content of Jasperoid
Class
Sedimentary Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
-
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock