A friend offers you money for an a necklace, but you refuse to sell because you obtained the necklace from a friend who died.
You now consider that necklace to have "personal" value (value that you can't put a price tag on).
Question
Is there a better word than "personal" that better describes the value of the object?
"Personal" does not express the exact nature of the situation, as it lacks the true attachment to the item (it came from a special person).