Definition
Rhyolite is a fine-grained igneous rock which is rich in silica
Appinite is an igneous rock in which the crystals are so fine grained that individual minerals cannot be easily distinguished
History
Origin
North America
-
Discoverer
Ferdinand von Richthofen
Unknown
Etymology
From German Rhyolit, from Greek rhuax lava stream + lithos stone
From the variety of Lamprophyre Greek lampros bright and shining + porphureos purple
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
Volcanic
Plutonic
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Opaque Rock