I always subscribed to the DnD description for any of the races, for gnomes in this case it would be like so:
DnD Monster Manual 3.5 wrote:
This humaniod stands a little more than half as high as a human. It has a compact build, dark tan skin, fair hair, and large eyes.
Gnomes are inveterate explorers, tricksters, and inventors. They have a knack for both illusion and alchemy.
Gnomes stand 3 to 3-1/2 feet tall and weigh 40 to 45 pounds. their skin color ranges from dark tan to woody brown, their hair is fair, and their eyes can be any shade of blue. Gnome males prefer short, cafefully trimmmed beareds. Gnomes generally wear leather or earth tones, though they decorate their clothes with intricate stitching or fine jewelry.
I leave out the parts that contradict in game mechanics about age and such. Also note that there are three races of gnome. The above would be the common Rock Gnome.
Svirfneblin wrote:
This humaniod stands a little more than half as tall as a human. It has a wiry, gnarled physique, stone-colored skin, and large gray eyes. It is bald.
Also called deep gnomes, svirfneblin are said to dwell in great cities deep underground.
A scirfneblin has wiry, rock-colored skin usually medium brown to brownish gray. Only males are bald; females have stringy gray hair.
Forest Gnome wrote:
This exceptionally small humaniod has moss-colored skin, dark hair, and brown eyes.
They are the smallest of gnomes, averaging 2 to 2-1/2 feet in height, but look just like regular gnomes except with bark-colored or gray-green skin, and eyes that can be brown or green as well as blue.
Gnome Bard courtesy of Wizards(R C and anything else to keep from being sued.)
Gnome Wizard again care of Wizards.