Definition
Greywacke is defined as a dark coarse-grained sandstone rock which contains more than 15 per cent clay
Syenite is a coarse-grained igneous rock which is composed mainly of alkali feldspar and various ferromagnesian minerals
History
Origin
-
-
Discoverer
Unknown
Unknown
Etymology
From German Grauwacke, from grau grey + wacke
From French syénite, from Latin Syenites (lapis ) (stone) of Syene
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, Fine Grained Rock, Medium Grained Rock, Opaque Rock