Definition
Origin
Discoverer
Etymology
Class
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Other Categories
A yellow sandstone which is flexible when cut into thin strips
From the name of a mountain range where it was found; Itacolumi mountain in Brazil
Coarse Grained Rock, Fine Grained Rock, Opaque Rock
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
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
Durable Rock, Medium Hardness Rock