Jakmanite 632

Jakmanite 632, or just Jakmanite, is a substance that was not normally picked up by the sensors of a starship. This substance, which had no naturally occurring sources, was the radioisotope byproduct of high-energy yurium decay.

Furthermore, along with invidium, saltzgadum, selgninaem, and lucovexitrin, it was one of only five undetectable substances that can exist in a nitrogen-oxygen atmosphere, and which can alter the molecular structure of glass.

Jakmanite had a half-life of about fifteen seconds and was thereby ruled out as having caused the malfunctions aboard the USS Enterprise (NCC-1701-D) in 2366, as there would not have been enough time to spread the substance all over the ship. 

ジャクマナイト