wacke, wak′e, n. German miners' term for a soft, grayish kind of trap-rock.
wackelfiguren means figures made of wacke, a greenish-gray mineral, soft and easily broken.
The material of the rock here is wacke, in which there are many flints.
rock resembling sandstone, 1803, from German Wacke, from Middle High German wacke "a large stone," from Old High German wacko "gravel," probably from Old High German wegan "to move." A miner's word, brought into geology by German geologist Abraham Gottlob Werner (1750-1817).