You must have GRIMSTONE and RED BLOCK to make DARK RED BLOCK. You can find this item in color blocks category. DARK RED BLOCK is good to plant before you head to some parkours. Unfortunaltely durability information is not available. There is no data about seedratio. Oops, there is no entry in the database about gemratio. If you know something, please share. Currently we do not yet have knowledge about the blockratio of DARK RED BLOCK.