Definition
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Etymology
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Other Categories
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
Travertine is a mineral consisting of layered calcium carbonate formed by deposition from spring waters
From Italian travertino a kind of building stone, from Tiburs, adjective from Tibur (Tivoli), in Italy
Durable Rock, Medium Hardness Rock
Fine Grained Rock, Opaque Rock