Definition
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
Marble is a non-foliated metamorphic rock which is composed of recrystallized carbonate which is formed when limestone is exposed to high temperatures and pressures over a long time
History
Origin
Egypt
Egypt
Discoverer
Unknown
Unknown
Etymology
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
From the Greek marmaros, shining stone and also from the English word marmoreal meaning marble-like
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
Plutonic
-
Other Categories
Fine Grained Rock, Opaque Rock
Medium Grained Rock, Opaque Rock