Definition
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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
Appinite is an igneous rock in which the crystals are so fine grained that individual minerals cannot be easily distinguished
From the variety of Lamprophyre Greek lampros bright and shining + porphureos purple
Durable Rock, Medium Hardness Rock
Coarse Grained Rock, Fine Grained Rock, Opaque Rock