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
Dolomite is a sedimentary rock containing more than 50 percent of the mineral dolomite by weight
History
Origin
Ethiopia
Southern Alps, France
Discoverer
Obsius
Dolomieu
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From French, from the name of Dolomieu (1750–1801), the French geologist who discovered the rock
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
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock