MikeH

Answer: I think she wanted people to stop focusing on this valuable necklace. She wanted them to care more about love, and the Titanic passengers who died.

Answer: The necklace is called "The heart of the Ocean." While in the middle of the ocean, Rose had her heart captured by Jack Dawson. Rose returned the diamond to the ocean in the exact place where her heart was taken by Jack. As she says at one point, "A woman's heart is a deep ocean of secrets"

Ssiscool ★

Answer: She basically gave it back to the ship. It was a symbolic gesture towards Jack as basically he died because of it.

lionhead

Chosen answer: Even though Rose repeatedly spurned Cal's affections in favor of Jack, Cal still maintained feelings of love and devotion for her. Cal did, with Jack's help, encourage Rose into a lifeboat in order that she might be saved. In the process, he told her that he had an arrangement with a ship's officer for another boat in another part of the ship which he and Jack could board. But that was a lie. He never had any intention of helping Jack. Jack had already surmised that Cal was lying, but played along in order to help convince Rose to save herself. Cal revealed the truth to Jack as the boat was being lowered. It seems Cal believed (or hoped) that once Jack was out of the picture, Rose would become the kind of wife he desired. However, after Rose abandons the lifeboat, and returns to the Titanic, Jack runs after her so they can live or die together. At that point, it finally becomes obvious to Cal that he will never have her. In his rage and jealousy, he lays chase, and unsuccessfully attempts to shoot them with his manservant's gun as they disappear into the flooding dining room.

Michael Albert

Answer: I believe the chase was also an ingenious way for Cameron to show flooding in various parts of the luxury areas that had previously been shown in its opulence, a good juxtaposition.