1 Definition
1.1 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
1.2 History
1.2.1 Origin
1.2.2 Discoverer
Marcus Vitruvius Pollio
Obsius
1.3 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
1.4 Class
Sedimentary Rocks
Igneous Rocks
1.4.1 Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
1.5 Family
1.5.1 Group
1.6 Other Categories
Fine Grained Rock, Opaque Rock
Opaque Rock