Finalflash50 Yes but it is matter. The element I want should be like diamond but breaks under pressure, so in that case it is antimatter proof. And I never said wall was solid.
Finalflash50 And for me they would be antimatter resistant so that would be just fine! And the powder it makes after being pressurized is invincible and antimatter can't eat it.
Antimatter is a utility element anyhow that's made for gobbling stuff up. Due to lack of eye candy it isn't really the greatest for a bomb unless you can mastermind a way to pour stuff into it suddenly from all sides AND get thunder or something to splode after.