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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
Phonolite is an uncommon extrusive igneous rock volcanic rock of intermediate chemical composition between felsic and mafic
From the Greek meaning sounding stone because of the metallic sound it produces if an unfractured plate is hit
Durable Rock, Medium Hardness Rock
Fine Grained Rock, Opaque Rock