When Set, Teardrop increases base HP by 9, base Psynergy Points by 2, bast Agility by 2, and base Luck by 1.
When Teardrop is unleashed in battle, the selected Downed Adept has a 70% chance to be revived, and their HP restored to 60% of their maximum HP.
In Dark Dawn, Teardrop's unleash animation visually resembles the user summoning the 3D model of Teardrop out of a large blue flash above the target ally. The background dims, and a large, circular, light-blue field forms under the target's feet. At the same time, two water droplets drop onto the field and create large, slow splashes, and then a third droplet drops down through the target's body and makes a large splash around the target that engulfs the target in a vertical beam of blue light. The blue beam disappears as a large collection of thinner, greenish beams circle around it.
Golden Sun: Dark Dawn: Teardrop is located behind the waterfall in the left screen of Kolima Junction. It cannot be gotten just by entering the junction from the west entrance on the overworld, something you can do as soon as you access the Morgal region, because the river here is not appropriately bridged. You must have progressed through the story until you have triggered the cutscenes at the screen to the right of that, which is only reached once you have played through Kolima Forest below. When you enter this left screen of Kolima Junction from the right, roll a log left to where two other logs are group against a boulder, then cast the Crush Psynergy on the boulder to make a bridge. Hop north of the right log in the water and Teardrop will automatically jump out from behind the waterfall so that you can collect it without a battle. This Djinni, like many others in the Morgal region, can be permanently missed once the final gate in the depths of Belinsk Ruins is entered.
General: Teardrop is not useful among the Djinn that can be used to revive party members due to having only a 70% chance to revive a Downed ally, and only reviving up to 60% of the target's health if it works. Water of Life and the Revive Psynergy are much more useful because they have a no-nonsense 100% chance to revive a downed ally to 100% health, and there is one other Djinni that matches the power and usefulness of the aforementioned item and Psynergy. These should always be used in place of Teardrop when available.
Golden Sun: Dark Dawn: Teardrop is identical to the Mars Djinni Cinder, found early in the game, and while Cinder had plenty of time to potentially prove itself useful to the party because it was one of the only reviving effects the party would have for a long while, Teardrop is gotten at a point when the Revive Psynergy is available and more Waters of Life are present. Teardrop is likely never going to be used, especially considering that later in the game the Mars Djinni Glow joins with Eoleo; its 80% chance to revive an ally to 80% health is far more reliably useful for at least a short amount of time. Glow, in turn, will be obsoleted by the 100% reviving effect of the Mars Djinni Tinder, found in Tonfon.
None of this is to mention the end of the game and the postgame beyond that; The Tua Warriors at Apollo Sanctum guarantee dropping a Water of Life every time they are defeated in a battle, and there is no limit to how many Waters of Life you can amass, and amass easily. Should enough Tua Warriors be fought that every Adept has their own collection of Waters of Life to use in the final battle and the postgame, none of the reviving Djinn should ever be used for the sake of their effects. The only purpose to Unleashing them at that point is setting up for a summon, and even then, other Djinn are typically better alternatives unless another Adept happens to be Downed at the same time. In this case, Teardrop may well still not be worth using.