Definition
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth
Cataclasite is a type of cataclastic rock that is formed by fracturing and comminution during faulting. It is normally cohesive and non-foliated, consisting of angular clasts in a finer-grained matrix
History
Origin
Ethiopia
Swiss Alps, Europe
Discoverer
Obsius
Michael Tellinger
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From the Italian word cataclasi
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
Volcanic
-
Other Categories
Opaque Rock
Fine Grained Rock, Opaque Rock