(Never place your CPU like the image above, it's just an example of what they look like)
There are only two manufacturers for CPUs, Intel and AMD. (See my section on Intel vs. AMD here)
Clearly shown on the image at the top of this page, the silver side is the top, and the gold dots are the bottom.
The top is a highly polished aluminum heatsink which has to be connected to a external cooler.
The bottom is made up of a bunch of tiny golden contact pads or pins that connect it to the motherboard.
(more to come)