Definition
Origin
Discoverer
Etymology
Class
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Other Categories
Oil Shale is a fine-grained sedimentary rock from which oil is extracted
From Old English scealu in its base sense of thing that divides or separate
Fine Grained Rock, Opaque Rock
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.
From the village of Luxulyan in Cornwall, England, where this variety of granite is found
Coarse Grained Rock, Opaque Rock