Grawacke or Grauwacke: How To spell?

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

Word contains consecutive vowels 'AU' in between alphabets gr & wacke is misspelled as 'A' as letter 'U' is phonetically ignore
Wrong Spelling: gr-a-wacke
Correct Spelling: gr-au-wacke
Explore spell check of Grauwacke to spell without errors.