Treasure
While it might seem obvious that treasure consists of shiny pretty things usually found in chests that may be buried or hidden, there is more to the game mechanic of transporting and making a profit from treasures than simply finding that golden goblet. Treasure is also considered an art object to give an indication that there is a level of craftsmanship involved in the item rather than being only a chunk of valuable metal, a huge pile of coins or a large gem. The Gold Piece value of an object will often be more than the combined values of the individual pieces that make up the object because of artistic merit.
All treasure is given a value and a bulk or volume and both are typically given in Gold Piece values. The value is based on both the material the object is made of and the artistic merit of the item. Artists can create masterpieces of simple materials. A wood carving by an elven artisan could be worth far more than a gold necklace made by an average goldsmith.
Treasure bulk is given in gold piece value also for ease of how to carry the item. If there is not a given weight for an item, the volume in gold pieces can be used to determine how bulky the item is and how it can be carried. A necklace might have a value of 200 gold pieces and a volume of 10 gold pieces. In this case the necklace would fit into a small belt pouch and still have room for 4 large gems. In practice most treasure items will have actual dimensions to help guide which container to use.