Sand Dollar



A Sand dollar is a type of shell. It can clean up water pollution.

The Battle of the Labyrinth
In The Battle of the Labyrinth, Percy gets a sand dollar as a gift for his 15th birthday from his father Poseidon. Not knowing when or how to spend it, Percy adds it to his camp necklace.

The Last Olympian
In The Last Olympian, Percy uses his sand dollar during The Battle of Manhattan. He gave half of it to The East River spirit and the other half to The Hudson River spirit in exchange for keeping Kronos' armies from crossing the East and Hudson rivers respectively. Percy manages to convince the two rivers to stop quarreling and drown Kronos' army.