Definition
Rhyodacite is an extrusive volcanic rock intermediate in composition between dacite and rhyolite
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
History
Origin
USA
Hawaii Islands
Discoverer
Unknown
Unknown
Etymology
Rhyo lite + dacite : a rock intermediate between rhyolite and dacite that is the extrusive equivalent of granodiorite
From Greek pikros bitter + -ite, 19th century
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
Volcanic
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock