Definition
Origin
Discoverer
Etymology
Class
Sub-Class
Group
Other Categories
Greywacke is defined as a dark coarse-grained sandstone rock which contains more than 15 per cent clay
From German Grauwacke, from grau grey + wacke
Fine Grained Rock, Opaque Rock
Boninite is a mafic extrusive rock which is high in magnesium and silica content, formed in fore-arc environments, typically during the early stages of subduction
From its occurrence in the Izu-Bonin arc south of Japan
Fine Grained Rock, Opaque Rock