Zechsteun or Zechstein: How To spell?

The word Zechsteun is misspelled against Zechstein, a noun meaning "The upper division of the Permian (Dyas) of Europe. The prevailing rock is a magnesian limestone."

Word contains consecutive vowels 'EI' in between alphabets zechst & n is misspelled as 'EU'
Wrong Spelling:  zechst-eu-n 
Correct Spelling:  zechst-ei-n 
Check more misspelled words of Zechstein to spell it correct.