Laracite

Laracite was an inert crystalline compound formed in interstellar space and sometimes found on planets or in clay or metal artifacts. Different isotopes formed in different regions of space, allowing xenoarcheologists to use traces of laracite to deduce the origins of a particular artifact. (Star Trek Online: Valkyries)

In 2407, Ferengi xenoarcheologist Doctor Mor found traces of a laracite isotope unique to the Dragon's Head Nebula in ancient Japanese pottery on Earth, giving credence to his theory of prehistoric contact between ancient Japan and an alien civilization in that area. ("Survivors of Yamatai")