- a nonporous, dark-colored sandstone containing angular particles of other rocks
- a fine-grained conglomerate resembling sandstone
Origin of graywackeAnglicization of German grauwacke: see gray; eastern; English wacke, a rock like sandstone ; from German
Any of various dark gray sandstones that contain shale.
Origin of graywackePartial translation of German Grauwacke : grau, gray + Wacke, rock (from Middle High German, from Old High German waggo, boulder; see wegh- in Indo-European roots).
(countable and uncountable, plural graywackes)
- Alternative form of greywacke.