Definition
Rhyolite is a fine-grained igneous rock which is rich in silica
Travertine is a mineral consisting of layered calcium carbonate formed by deposition from spring waters
History
Origin
North America
Italy
Discoverer
Ferdinand von Richthofen
Marcus Vitruvius Pollio
Etymology
From German Rhyolit, from Greek rhuax lava stream + lithos stone
From Italian travertino a kind of building stone, from Tiburs, adjective from Tibur (Tivoli), in Italy
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
Volcanic
-
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock