Definition
Troctolite is a mafic intrusive rock type. It consists essentially of major but variable amounts of olivine and calcic plagioclase along with minor pyroxene. It is an olivine-rich anorthosite, or a pyroxene-depleted relative of gabbro
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
History
Origin
-
Egypt
Discoverer
Christian Leopold von Buch
Unknown
Etymology
From German Troklotit, from Greek trōktēs, a marine fish (taken to be trout)
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Family
Group
Plutonic
Plutonic
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock