Treasure

Treasures are various items that can be be sold and/or bartered for services or equipment Upgrades.

Phantom Hourglass
In Phantom Hourglass, there are eight different kinds of treasures scattered across the World of the Ocean King, which can be found in chests in dungeons, pots, or bought from shops. There is no limit to the number of treasures there are: chests in the Temple of the Ocean King will replenish, as will the stock of shopkeepers.

Treasures can be sold for Rupees to the Teller of Treasures on Mercay Island, who will buy anything at any time, or to the Ho Ho Tribe, who will buy one random item at a time for a slightly higher price than normal. The price the different treasures sell for varies depending on the game; they can sell for as cheap as 50 Rupees and up to 800 or even 1500 Rupees.

They can also be bought in shops, found in dungeons (including the Temple of the Ocean King, where they will replenish every time the dungeon is left and reentered, making a supply of random treasures). In addition, by saving Nyave from monsters in the southwestern part of the Great Sea, Link will receive a large amount of treasures that had been picked up for him.

Treasures may also be swapped among friends for either other treasures or Ship Parts via Tag Mode and Battle Mode. Access to Freedle's magic boxes is required to trade. Doing so takes advantage of the random price differences for players. Lowly valued treasures on one Gamepak may be coveted ones to others.

The treasures are:

Spirit Tracks
In Spirit Tracks, treasure-hunting returns with 16 treasures for Link to find. The Pink Coral, Zora Scale, and the Helmaroc Plume are absent from Spirit Tracks, but the other treasures do make an appearance in the game, found most often within pots and chests. At Linebeck III's trading company, treasures may be sold for Rupees or traded for various upgraded Train Cars.

Common treasures such as Wood Heart, Bee Larvae, and Demon Fossil can be easily found by blowing the leaves northeast of Whittleton with the use of the Whirlwind. However, they can also be found by breaking the pots inside the cave that leads to the Fire Sanctuary. The more scarce treasures, such as Dark Pearl Loops or Palace Dishes, can be obtained by getting specific scores in minigames or by buying them from shops, such as Beedle's Air Shop or the Castle Town Shop. The extremely rare treasures, like Alchemy Stones or Regal Rings, can only won as prizes in special Train Stations such as Ends of the Earth Station, Slippery Station, or Lost at Sea Station. Alternatively, they are also won for mailing in Prize Postcards and getting the 1st prize.

The treasures are aligned in the Collection screen according to their rarity: the top row contains treasures that are common to obtain, while the bottom row's treasures are harder to find.

Skyward Sword
In Skyward Sword, there are 16 completely new treasures found as spoils from enemies or scattered in the overworld. Treasures can be exchanged at the Bazaar's Scrap Shop for equipment upgrades, such as the Banded Shield, or sold to Rupin at his home at night. Treasures can also be bought from a Sheikah Stone known as "The Moonlight Merchant" hidden in the cave near the waterfall in Skyloft after the final Silent Realm.

Treasures are categorized as either Rare Treasures or Small Treasures. Rare Treasures trigger a fanfare upon finding them (the same one played when finding Red and Silver Rupees, Small Keys, and Pouch Items, excluding shields), and are generally used to upgrade higher level items, such as ones that have already been upgraded at least once. (e.g., A Small Seed Satchel requires three Ornamental Skulls to be upgraded to a Medium Seed Satchel, but a medium Satchel instead requires one Golden Skull and a Blue Bird Feather to upgrade to a Large Seed Satchel). Aside from being worth more when selling to Rupin at night, they have no differences from regular treasures and are categorized in the same place, along with being used for the same purposes. This distinction also does not necessarily mean that all Rare Treasures are harder to find—Dusk Relics are often considerd to be one of the hardest treasures to acquire, yet they are classified as Small Treasures.

The likelihood of finding treasure increases when Link has the Treasure Medal.

Trivia

 * The new Hylian word for Hyrule can be read on the Ancient Gold Piece.
 * The Amber Relic and Dusk Relic resemble real world.
 * The Ornamental Skull is described as "the Bokoblin Symbol," and sure enough, every one in-game is seen with one on their belt. However, this is not new to Skyward Sword, as Bokoblins are seen wearing these skull-shaped belt buckles in The Wind Waker, their debut game. Oddly enough, though The Wind Waker also features a treasures/enemy drop system similar to that of Skyward Sword, Bokoblins do not drop these skulls, and instead humorously drop the butterfly-shaped Joy Pendants. Skull-like treasures in The Wind Waker instead come from the Moblin, who drop them in the form of Skull Necklaces.
 * Chuchus in Skyward Sword drop Jelly Blobs, strikingly similar to the Chu Jelly found in The Wind Waker and Twilight Princess. However, unlike those games, Jelly Blobs are used purely for upgrading items, and have no bearing on or relationship to the potions found in-game.
 * The Dark Lizalfos drops Lizard Tails, much like his standard green counterpart, but if one looks closely after defeating a Dark Lizalfos, it's shown that the tails they drop are purple, to match the color of their scales. However, unlike the distinction made for the Bird Feathers, Skulls and Relics, Dark Lizard Tails are not distinguished in any way from regular tails, and they count toward the same thing.

''See here for the translations for the treasures in Phantom Hourglass. See here for the translations for the treasures in Spirit Tracks. See here for the translations for the treasures in Skyward Sword.