Void Candle

Effect: A black candle producing light only where magic has been suppressed or is being hidden. In antimagic zones, Null Zones, or anywhere a Seal of Unmaking is active, it burns with steady white light as though perfectly normal. Reveals magical concealment: any illusion, invisible creature, or magically hidden object within 30 feet becomes faintly outlined in white. Cannot be extinguished by magical means.
Uses: One candle burns for 4 hours. Found and sold in sets of 1d4+1.

About

The flame comes from the boundary between deep lower-realm void and the rest of existence - a place where magic's absence is so total that the void itself becomes visible.

Carries the resonance of The Lower Realms