wacke
/ˈwækə/noun
mass noun
- Geology a sandstone of which the mud matrix in which the grains are embedded amounts to between 15 and 75 per cent of the mass【地质】玄砂石; 玄武土。
词源
early 19th cent.: from German， from Middle High German wacke 'large stone'， Old High German wacko 'pebble'.