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Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism
From Old French esclate, from esclat (French éclat)
Durable Rock, Medium Hardness Rock
Fine Grained Rock, Opaque Rock
Vogesite is a porphyritic alkaline igneous rock and is a variety of Lamprophyre which is dominated by essential amphibole, usually hornblende, and potassic feldspar
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