"small sliver of mother-of-pearl "

Decorative mother-of-pearl
Creative Commons Attribution Share AlikeDecorative mother-of-pearl - Credit: Kluka

Juli's greatest treasure is a small fish made from mother-of-pearl.  Mother-of-pearl (also known as nacre) is a strong, iridescent material produced by mollusks such as the oyster and the pearl mussel.  It is often used to make jewellery, buttons and other decorative items.