Non-Rectangular sprites in the sprite editor

When one has multiple sprites in one image, is it possible to haves sprites that

a) do not have a rectangular shape - so you could have a rectangle with a zigzag on one side for example b) that are rotated- so not horizontal

The reason I ask this is because I have a block that i would like to break with a jagged edge, and the easiest way i can think of is to have the original block sprite, but to also have two sprites on top of this in the sprite editor with a broken looking edge. If you can think of another way to do this without a seperate spritesheet then please share.

I know that this probably wasn't very clear, but if you have any questions please do not hesitate to ask and thank you for your help.

This is a 2d project on windows 8.1 and I am using unity 4.5.2f1