Ambassador Dara Mellon was a Federation dignitary in the 24th century who was present at a conference with delegates from the Romulan Star Empire on Earth on stardate 54103.7. The delegation came two months after the Watraii attack on the Romulan empire which itself was one year after the Dominion War.
Mellon had pure white hair which was caught up in an elegant corona of braids. She possessed clear blue eyes which showed a cool calculating mind. She was known for her charming political smiles and was almost as unreadable as a Vulcan. She was also known for her amazing ability for self-control.
She attended many ambassadorial missions but one of the reasons for her success was her ability to accept that others might know more than she did on a specific subject. (TOS - Vulcan's Soul novel: Exiles)