For Philosopher's Stone (賢者の石, Kenja no Ishi), you may be looking for:
- Philosopher's Stone (Agito) - The orb in the center of the Altering belt, from Kamen Rider Agito
- Philosopher's Stone (Wizard) - a magic stone from Kamen Rider Wizard
- Philosopher's Stone (Gotchard) - an item from Kamen Rider Gotchard