Definition
Scoria is a dark-colored extrusive igneous rock with abundant round bubble-like cavities
Luxullianite is a rare type of granite, known for presence of clusters of radially arranged acicular tourmaline crystals which are enclosed by phenocrysts of orthoclase and quartz in a matrix of quartz, tourmaline, alkali feldspar, brown mica.
History
Origin
-
England
Discoverer
Unknown
Unknown
Etymology
From late Middle English (denoting slag from molten metal), from Greek skōria refuse, from skōr dung
From the village of Luxulyan in Cornwall, England, where this variety of granite is found
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
Volcanic
Plutonic
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock