Meditation Crystal

Though this focus is usually a hand-sized crystal, the exact form (such as a wooden idol, an iron disk, and so on) may vary for some religions.

Source Adventurer’s Armory

A monk or paladin of the cleric’s faith may concentrate upon an activated meditation crystal, taking no actions for 1 minute, and regain 1 ki point or one use of lay on hands. Once activated, the crystal retains its energy until a monk or paladin uses it for this purpose or 24 hours pass.