In "Exposé", the diamonds owned by Howard L. Zukerman are kept in a Matryoshka doll. Once stolen, the doll remains in Nikki's Exposé bag. After the crash of Flight 815, Nikki and Paulo couldn't find the doll. Once Paulo located the bag, he transferred the doll into the back of the toilet inside The Pearl station. Paulo returned to the Pearl station and smashed the doll in order to get the diamonds that were hidden inside. He put the smashed remains back into the back of the toilet.
Matryoshka dolls originate from Russia, though some say their development was influenced by similar souvenir objects in Japan. Doll designs can vary considerably, though the design perhaps most commonly recognized is the peasant girl/gypsy artwork. Matryoshka dolls are traditionally at least six different dolls, decreasing in size and nested inside one another.
The dolls are often used a metaphor for successively hidden layers of meaning, each being a step to the next level of revelation.