I am trying to place a block using the block command for a custom reward, specifically I need it to be made out of dark prismarine. If it was an item I could specify minecraft:prismarine damage:2, but since its in the block command, I can only specify minecraft:prismarine and there is no capability to interpret the subID of 2 required to differentiate dark prismarine from prismarine. Based on my understanding of java(somewhat limited) I do not see any place to input the subID, and I have found no examples of custom rewards within the code or from other mods using block with a subID.

Huh, that is a good point. I will look into this to see if I have added this and it's just not documented or if I do need to add this