Ethereal Field

For the duration, you and your allies within 10 feet of you can detect the presence of magic within 30 feet of themselves. If anyone affected senses magic in this way, they can use their action to see an aura around any visible creature or object in the area that bears magic, and then learn its school of magic.

The spell can penetrate most barriers, but will be blocked by 1-1/2 foot of stone, 2 inch of common metal, a thin sheet of lead, or 4 feet of wood or dirt.