Shadowlight oil

Shadowlight oil was a slow-burning oil infused with the essence or fabric of the Plane of Shadow. When burned, it gave off a dim, shadowy light.

Description
A 1-pint flask of shadowlight oil weighed 1 pound (450 grams) and was valued at 5 gold pieces.

Powers
Functioning like regular lamp oil in most respects, shadowlight oil could be burned in any typical lamp, lantern, or other similar light source. Although its light was dim and never fully bright, it extended twice as far as the light of regular oil. For example, if a basic lamp burning regular oil illuminated to a distance of 15 feet (4.5 meters) and half-illumination to 30 feet (9 meters), such a lamp burning shadowlight oil produced half-illumination to 60 feet (18 meters). This was surprisingly useful on the Plane of Shadow: natural light sources were halved in range, but a shadowlight oil lamp was not.

It was also a slow-burning oil, with one pint lasting for 12 hours.

Creation
Shadowlight oil could be created by a master alchemist.

Uses
In the Year of Lightning Storms, 1374 DR, shadowlight oil was used by cultists of Shar to light lamps and lanterns at their hideout in the Lost Refuge in the Vast Swamp. They also used it light beacons through the Shadow Swamp.