Definition
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Etymology
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Ijolite is an intrusive igneous rock which is composed mainly of nepheline and an alkali pyroxene, usually aegirine-augite
From the first syllable of the Finnish words Ii-vaara, Iijoki, &c. commonly used geographical names in Finland, and the Gr. Xiflos, a stone
Durable Rock, Medium Hardness Rock
Coarse Grained Rock, Opaque Rock
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