Cathium

Cathium is a mineral found in many terrestrial gas giants. When formed naturally, it is found in the form of a fine powder, making it's harvesting a very tedious task. With the help of a mineral compressor, it can be turned into a solid form, often referred to as Cathium Quartz.

Uses
Cathium's main use is to be compressed with steel, forming the popular material, Plasteel.

However, several other uses for Cathium are also common. This includes the recipe for several medical injections, as well as an insect repellent (though only when in it's purest form).