I am not sure it will work in 1.8.9 but it works in 1.7.10
If you know, there is list of blocks.
Like Blocks.sand
If you pick up your block for modifying, then use some basic methods from Block class.
Example
Block b = Blocks.sand;
b.setHardness(6.0F) //Sets a hardness for given block
b.setTextureName(.......) //Sets texture for block.
b.setHarvestLevel("pickaxe", 3) //Sets harvest level for block.
And so on...
If I am wrong with this, simply write a reply or PM me.