Definition
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Discoverer
Etymology
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Other Categories
Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism
From Old French esclate, from esclat (French éclat)
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