Definition
Origin
Discoverer
Etymology
Class
Sub-Class
Group
Other Categories
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
Fine Grained Rock, Opaque Rock
Mylonite is a metamorphic rock formed by ductile deformation during intense shearing encountered during folding and faulting, a process termed cataclastic or dynamic metamorphism
From Greek mulōn mill + -ite
Durable Rock, Medium Hardness Rock
Fine Grained Rock, Opaque Rock