What kind of snake is silver with black diamond shape on it back?

well...it depends on what part of the country or world you are living in....if you are outside the united states, i have no idea. i assume yo are within the u.s. so most likely, the snake you are inquiring about is a type of rat snake. they actually vary somewhat in color, so without a pic, noone can be sure.

diamondback rattlesnakes also have diamonds on their back. they are usually a browner color but i can only assume anyone would recognize the rattles on any rattlesnake.

you may look up a pictorial directory for snakes in your area by preforming a search on google or Yahoo.