Ailment Agate

By all initial appearances, this coin-sized stone is a common gray agate with bands of white and black. But its magical properties are displayed when placed in contact with the skin of a living humanoid for 1 minute. The agate will change its color for the next 1 minute if the humanoid is suffering from any one of five types of ailments:

• Brown for diseases
• Pink for poisons
• Red for parasites
• Orange for allergic reactions
• Yellow for physical disorders

If the humanoid suffers from two or more types of ailments, then the one with the worst symptoms takes priority. If priority cannot be established, then priority is assigned randomly.