Gemstone

A Gemstone is a magical gem made by the Goddess of Destiny for Travelers to find. Once a Traveler collects all five gemstones, their weapon transforms into the Demon's Bane or the Demon's Woe and they may present it to the Goddess and obtain their wish.

Trivia

 * Before acquiring the Gem of the Spirits, the player must choose from four colored gems(red,blue, purple or green). Interestingly, no matter which color you choose, the gem in the Traveler's Sword always appears green in color.
 * The Demon's Bane appears to have two of each gemstones, with five on the and the others floating around the blade.
 * This also applies in the Demon's Woe.
 * Although it says "Demon's Woe" in Mitsuru's stats in Brave Story: New Traveler, his staff doesn't change its appearance.