Brittlestone, Crumblestone, Burststone, Shatterstone

I think there should be a few new cave blocks in Minecraft.

Brittlestone would have the ability to fall like sand when it is stepped on too many times and when it hits the ground it will dissapear. It would have 4 variants containing Brittlestone, Cracked Brittlestone, Fragile Brittlestone, and Shattered Brittlestone. Shattered Brittlestone is the stones final form as it falls afterward and then breaks.

Crumblestone is the most stable stone in the Brittlestone cave because it is just like Brittlestone but it only cracks when jumped on.

Burststone is stone that when touched by any entity will explode a  3 x 3 radius around it destroying the stone and setting off more Burststone.

Shatterstone instantly breaks when touched by an entity and shoots out shards of Shatterstone in all directions dealing 3 damage points if hitting an entity.