Definition
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Etymology
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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
From the English mud and stone, from low German mudde and stainaz
Fine Grained Rock, Opaque Rock
Tonalite is a coarse-grained plutonic rock consisting mainly of sodic plagioclase, quartz, and hornblende or other mafic minerals with phaneritic texture
From Tonale Pass, northern Italy, + -ite1
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock