Definition
Greywacke is defined as a dark coarse-grained sandstone rock which contains more than 15 per cent clay
Minette is a variety of Lamprophyre and is porphyritic alkaline igneous rock which is mainly dominated by biotite and potassic feldspar
History
Origin
-
-
Discoverer
Unknown
Unknown
Etymology
From German Grauwacke, from grau grey + wacke
From French mine ore, mine + ette
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, Opaque Rock