Definition
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Discoverer
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
Hyaloclastite is an aggregate of fine, glassy debris formed by the sudden contact of hot, coherent magma and cold water or water-saturated sediment
Fine Grained Rock, Opaque Rock