The Moonstone is a giant quartz rock near Highstones. It is positioned in a cave called Mothermouth by the Clans. Medicine cats from all four clans typically travel to the Moonstone every half month to share tongues with StarClan. They usually take their apprentices and all go together. When the past leader of a clan dies or retires, their deputy must take over. This means the new leaders of the clans must also travel to the Moonstone to receive their nine lives from StarClan.