Tear's PendantWhile playing Tales of the Abyss for the second and third time, I came to realize that Tear's pendant functions as a symbol of the relationship between Luke and Tear. The pendant was her only memento of her mother and thus was very important to her. When she gives it to the coachman to pay for a ride for Luke's sake, it can foreshadow just how important Luke will be to her in the future. When she does give it away, she hesitates a little and seems to be saddened by the fact she had to use it to pay. Luke, being the arrogant brat he was in the beginning, took no notice. Tear likely considered it punishment for her carelessness of not realizing Luke could use the Seventh Fonon as well. She believed it was her fault for dragging Luke outside of his manor and she should have to suffer to make up for it.
When they run into the coachman again, he tells Luke and Tear that he sold it to a traveling merchant. At this point, Luke actually cares about Tear and her feelings and is determined to get it back for her. Tear insists it's fine. Luke realizes how important it is to her now and wanting to get it back to make her happy displays the development of their relationship up until that point. He tells her when they find the merchant, he will buy the pendant back for her and they continue their journey.
Luke finally finds the merchant in Grand Chokmah, who will only sell it to them for 100,000 gald. Tear tells Luke to just forget it because the price was way too expensive. Luke refuses, though. If you have enough money on you to buy it, Luke will get it on the spot and give it to her. If not, he says he will ask his father for the money to pay for it despite her protests. Once the pendant is obtained again, Tear thanks Luke and holds it close to her. The pendant was important before, but it now represented how Luke cared about her enough to go through the trouble to get it back for her. I have a feeling it meant more to her now because of that. Tear tells him how important it was to her and Luke gained more appreciation as to how hard it was for her to give it up just so he didn't have to walk back to Baticul. Their relationship has grown tremendously since that point in time and likely caused Luke to reflect on how poorly he treated her in the beginning. He originally did not care about Tear or her pendant. But, he grew to care for her deeply and is able to get it back for her because he is sensitive to her feelings. A great amount of time elapses between these three points in their relationship and their interactions around the pendant represent what stage of their relationship's evolution they are in.