Red Matter Block
Red Matter Blocks are extremely durable and can even withstand a nuclear explosion, similar to their lesser equivalent, the Dark Matter Block. However, while it may survive a nuclear explosion, it does not offer any blast protection, as the blast passes right through it. Also, it is possible for Red Matter Blocks to be melted by being in close proximity to a nuclear reactor that is overheating.
Red Matter Blocks cannot be pushed by pistons.
NOTE: You cannot craft this block back into raw Red Matter. But you can condense it back to Red Matter with no loss.
Also note: This block cannot be mined with anything short of a Red Matter Pickaxe.
While sprinting over the Red Matter Block, the particles of Glowstone Blocks will appear, rather than a special particle for a Red Matter Block.