Question: did they ever find the heart of the ocean necklace

Answer: Yes, On the night of the sinking the diamond changes hands a few times between Rose and Jack, resulting in Jack being framed of its theft by Rose's fiancé Cal. As the ship starts to list dramatically it becomes quite clear that the unsinkable Titanic will indeed sink. With this in mind Rose's fiancé, Cal, returns to the suite and empties the safe placing the precious gem in his overcoat. Later on Cal puts this same coat on Rose as she enters a lifeboat, forgetting about the diamond in its pocket. It is not thoroughly stated whether or not Rose (Gloria Stuart) tells Brock Lovett about Cal emptying his safe along with the diamond, it is assumed she doesn't as Lovett doesn't have any follow up questions. At the end of the film, Rose walks alone to the stern of the salvage ship and opens her hands revealing both the necklace and Rose's identity as Rose Dewitt Bukater. While examining the necklace, Rose has a flashback to 1912 on her arrival in New York and discovers the necklace in the overcoat. Returning to the present, Rose, with a smile, drops the necklace from her hand into the water presumably above the Titanic wreck site.