The Pearl Necklace is treasure that can be obtained in the episode Coopers of the Caribbean in Sly Cooper: Age of Thieves. It is worth 235 coins and the time needed to reach the safehouse is thirteen seconds.
"Such a splendid necklace is perfect for any special occasion, like weddings and celebratory dinners. Before she became a pirate, Henriette was given one to wear by her father, Victor Cooper, as a birthday present. This is, in fact, that same necklace."
It is located behind the local pub, where a special button must be pressed to open the way to its cellar. Murray's Thunder Flop makes him the only member of the Cooper Gang capable of obtaining this treasure.