I've been thinking about this for some time, and I came to the decision of presenting this suggestion, from my point of view it could be a great addition to the game, it is said that the 80% of the universe is made out of dark matter, so I thought, why not using it in this game, some of the properties I thought for it to have is : 

1: a redish black or a purple black color.

2: gas state, not flamable, neither soluble

3: highly explosive under pressure, also generate energy when having negative pressure 

I wish its taken in consideration.

Unanuep