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
Claystone is a fine-grained, dark gray to pink sedimentary rock which mainly consists of compacted and hardened clay
History
Origin
Ethiopia
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Discoverer
Obsius
Unknown
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From English clay and stone as the rock contains more amount of clay
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
Volcanic
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Other Categories
Opaque Rock
Fine Grained Rock, Opaque Rock