Hoard of the Dragon Queen - Dragons of Faerûn
Monocle of Magic Detection
This item came into Nissa Timbers’s possession during seasonal festivities around the time of arrival in Waterdeep.
Wondrous item (requires attunement)
The animal or person wearing this item can sense the presence of magic within 30 feet. If magic is sensed in this way, an action will allow the person to see a faint aura around any visible creature or object in the area that bears magic, and you learn its school of magic, if any. The monocle can penetrate most barriers, but it is blocked by 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt.