Definition
Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks
Adamellite is a coarse-grained porphyritic igneous rock, a variety of Monzogranite and dominated by phenocrysts of orthoclase in a granular groundmass of perthite, plagioclase and quartz
History
Origin
-
Italy
Discoverer
Unknown
Unknown
Etymology
From the Middle High German verb gneist (to spark; so called because the rock glitters)
From German adamellit and from Monte Adamello, a mountain in Italy, its locality
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Family
Group
-
Plutonic
Other Categories
Coarse Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock