Blue Crystal pendant from the Final Fantasy series of games.
11.5g / 17mm x 45mm pendant with a 500mm steel chain.
Crystals (クリスタル, Kurisutaru), also called orbs and spheres, are legendary and often elemental objects that have appeared in every game in the main Final Fantasy series. Even in games where they are not a central plot point, there has been at least some reference to them. Crystals often have power over natural phenomena, and function as a powerful source of magical energy. Many antagonists focus their efforts on seizing the crystals to gain power towards their goal.