Oil of Revelation

This bright oil, first created by humans as a tool to help them fight in darkness, holds flecks of tiny gemstones in suspension and smells like a struck matchstick. The first time a weapon coated with this oil damages a creature, the wound glows with light for 1 minute. If the creature is Invisible, the light's position means it's merely Hidden to creatures that would otherwise be unable to see it, rather than Undetected. The light also negates the Concealed condition due to lighting conditions. If the coated weapon doesn't damage a creature within 1 hour, the oil sloughs off and loses its power.