Roughening
From verrauhen occurs when a passage (geology) as he pursues in minerals is poorer and the deaf rock in relation to ore increases more and more.
Individual evidence
- ^ Herbert Stahl (editors), Gerhard Geurts , Hans-Dieter Hilden, Herbert Ommer , Siegfried Raimann: Das Erbe des Erzes, Volume 4, Der Lüderich , Bergisch Gladbach 2008, ISBN 3-932326-52-0 , glossary p. 251