Adamantan or Adamantean: How To spell?

The word Adamantan is misspelled against Adamantean, an adjective meaning "adamant; hard as adamant."

Adamantean has vowels 'ea' together mispronounced as 'a'
Word contains consecutive vowels 'EA' in between alphabets adamant & n is misspelled as 'A'
Wrong Spelling:  adamant-a-n 
Correct Spelling:  adamant-ea-n 
Browse incorrect spellings of Adamantean to spell it good.

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