What is the weakest block in minecraft?

Take a search for the "minecraftWiki" on Yahoo/google and it will give you all the information you ever wanted to know about minecraft.

My guess would be Sand. (or Ice) Actually Sand, Sand Stone, Earth block, and tree seem about the same hardness. You can use a stone Pick/Axe on those easily but you need to use an Iron pick/axe on "ores", like coal, etc, to keep from destroying them.