Nullium

Nullium is a relatively common, dull gray metal which can be found on many planets and in asteroids across the galaxy. Its primary properties include the ability to withstand greater temperature variations than many metals without cracking or warping, as well as possessing poor mana conductivity, allowing it to function as an insulation material for work which requires keeping mana out. However, nullium is incredibly brittle, making it easy to damage or destroy.

Nullium is primarily used in the creation of ritual circles by magi, in magical 'clean rooms', and for magical furnaces where outside mana could ruin the results.
Although nullium is magically non-conductive, it can still be affected by magic.