Antimatter
Antimatter (aka Sharty Killing Coal or Coal 2) is a new form of Brimstone. Its quality is so atrocious that it gets universally hated by every Chud. Sometimes, certain examples of Antimatter can't even be named due to how ugly and terrible it is.
In relation to real life
It’s real life counterpart is very difficult to create and so volatile it can't touch any form of regular matter without creating a violent reaction.
Drawing comparisons, its quality adjective counterpart is destructive, but very hard to create. Unlike brimstone and dust, which can occur naturally, isolated antimatter is always a artificial and deliberate effort to create.
In relation to other rankings
Antimatter is the second rarest known quality of post. It is only more common than a sharty saving diamond glisterald, which hasn't been identified yet. Scientists have concluded that this is due to the fact that the average soyteen has a higher capacity to seethe than to appreciate a proper gem.