Gruwacke or Grauwacke: How To spell?

The word Gruwacke is misspelled against Grauwacke, a noun meaning "Graywacke."

Word contains consecutive vowels 'AU' in between alphabets gr & wacke is misspelled as 'U' as letter 'A' is phonetically ignore
Wrong Spelling: gr-u-wacke
Correct Spelling: gr-au-wacke
Check more misspelled words of Grauwacke to spell it correct.