Varcidium

Farcidium is a metal-like material that when struck with another piece of farcidium or Mana it emits a high frequency sound that damages DNAliens' ears as demonstrated in Undercover when kevin absorbed it.

Appearance
Farcidium is brass-colored but when ben's team was trapped in Los Soledad it was more copper-colored.

Trivia

 * When ben's team was trying to escape from Los Soledad, Gwen purposly hit Kevin (absorbed farcidium) hard because he was making fun of her and Cooper.
 * High frequency sound waves are sound waves with a low wavelength and high frequency.