adamantine vs adamant

adamantine is not a noun while adamant is a noun.

Word	Noun	Adjective	Verb	Adverb
adamantine	No	Yes	No	No
adamant	Yes	Yes	No	No

As adjectives, adamantine and adamant are synonyms defined as:

adamantine and adamant: impervious to pleas, persuasion, requests, reason

Other synonyms of adamantine include inexorable, intransigent.

adamantine (noun)	adamant (noun)
	very hard native crystalline carbon valued as a gem

adamantine (adjective)	adamant (adjective)
consisting of or having the hardness of adamant	impervious to pleas, persuasion, requests, reason
having the hardness of a diamond
impervious to pleas, persuasion, requests, reason