The Metal Detector is an informational item that displays a message to the player when valuable objects are in the player's vicinity (ores, chests, Life Crystals, Life Fruits, or Pots), and includes the object name (eg. "Chlorophyte Ore detected nearby!"). When multiple valuables are detected, only the one with the highest value is noted. The Metal Detector has a 1/2 chance (50%; 100% chance in Expert Mode) to be dropped by the Nymph, a rare underground enemy.
Like most informational items, the Metal Detector does not reveal the location or direction of the detected object. It also does not detect Gems.