Definition
Travertine is a mineral consisting of layered calcium carbonate formed by deposition from spring waters
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
History
Origin
Italy
Ethiopia
Discoverer
Marcus Vitruvius Pollio
Obsius
Etymology
From Italian travertino a kind of building stone, from Tiburs, adjective from Tibur (Tivoli), in Italy
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Opaque Rock