noun
(also rauchwacke)
Geology A dolomitic limestone of the Upper Permian or Zechstein group in Germany, corresponding to the magnesian limestone of England; (more generally) a magnesian limestone thought to resemble this.
Origin
Early 19th century; earliest use found in Annals of Philosophy. From German Rauhwacke from rauh (now rau) rough + Wacke.
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