I have a friend who WAS involved in the Earthblock.com business. But, when they tried to test the block in water it dissolved and also soaked water up like a sponge. It seems also that the blocks are not patent pending as first stated and this is also now removed from their marketing site.
IF anyone has proof that this Earthblock is for real, please let us know.
I also have looked into Enviro-bricks and this product is incredible. It is waterproof and is an inter-locking brick. Check it out at http://www.enviro-bricks.com