Bluestone

probably the first use would be that when place next to redstone it would not connect to it allowing you to make compact redstone circuits. Also the bluestone would also be able to be placed vertically which would also be very useful for redstone circuits. possible other things such as a bluestone torch which would work like a redstone torch but with bluestone instead of redstone and another thing that could be used would be a power transformer which allows you to turn bluestone into redstone and vice verser you connect redstone in the side and then put bluestone wire on the other side and when you put power into the redstone the bluestone is powered. uses for this could be that you don't have much bluestone dust and there would be an bluestone powered furnace or something and this furnace when given a bluestone wire current and you put coal into the fuel slot it will smelt much faster than a regular furnace.
Bluestone would either be found in the world or be crafted with redstone and something blue such as lapis lazuli

I feel this would make minecraft a much better game.