Definition
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.
Mudstone is a fine-grained, dark gray sedimentary rock, which is formed from silt and clay and is similar to shale but has less laminations
History
Origin
England
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Discoverer
Unknown
William Smith
Etymology
From the village of Luxulyan in Cornwall, England, where this variety of granite is found
From the English mud and stone, from low German mudde and stainaz
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Family
Group
Plutonic
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Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock