Amulet of Demon Detection

This item consists of a red round ruby gemstone with an odd matte finish, which is held in the grasp of a four-taloned silver claw. The claw, in turn, is suspended from a sturdy leather thong which appears to have been dyed a dull red color. (The thong is actually a treated and preserved stretch of demon sinew, taken from the muscles of a defeated demon.) Wearing the thong around one's neck, in contact with the skin, activates the detection power of the amulet. If any being from the demonic plane of existence come with 60' of the amulet's wearer, they feel a cold shiver run up their spine, and then the skin on their scalp tightens to a painful degree. At the same time, any demonic beings or entities visible on the prime material plan exhibit a faint red glow. (Demons that are invisible cause the spine and scalp reactions but will not exhibit the red glow.) A demon who is somehow magically or naturally screened from detection does not set off the item's abilities.