Definition
Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.
Rhyolite is a fine-grained igneous rock which is rich in silica
History
Origin
Indonesia
North America
Discoverer
Cornish Gossen
Ferdinand von Richthofen
Etymology
From Cornish gossen from gos, blood from Old Cornish guit
From German Rhyolit, from Greek rhuax lava stream + lithos stone
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
-
Volcanic
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock