A necklace is an item in Evony TKR (The King's Return).
Necklace is one of the collection items in the exhibition for the Art Hall. It is one of four parts in the Jewelry Hall. After the set is completed at three stars, you can trade additional Necklace fragments for gold.
The description of Necklace in Evony TKR says:
Expensive jewelries made from gold and silver. The important exhibits in Jewelry Hall.
Necklace is known to potentially be obtainable from opening Artwork Fragment Chest IV, Artwork Fragment Chest V and Artwork Fragment Chest VI. The links for each item are below:
Note: This list may be incomplete.