Simple and effective -
The Gold Pan, or Gold Dish as the Forty Niners called it, has been around for thousands of years. The earliest was probably the Batea, a large conical shaped pan carved from wood. The Batea was heavy an unwieldy and never gained popularity oustide of South and Central America.

The Forty Niner Dish was often carved from wood and there were also steel versions. The panner places the gold bearing gravel into the pan and places it under water. While swirling the water in the pan the miner allows the lighter materials to wash over the edge. The process continues until all of the lighter materials are washed away leaving the Black Sand (magnetite) and Gold. The small flakes and nuggets may be picked out by hand. The remaining Black Sand is saved for later refining.

The Gold Pan is an indespensible tool for any prospector. It it used to sample areas for Gold concentration and also for the cleanup of the materials in the sluice box.

Present-
Metal pans are still widely used but plastic pans are lighter and easier to work with and maintain. Plastic pans come in different colors, typically black, blue and green. These colors provide an excellent backdrop for spotting the gold. Some plastic pans are made with riffles molded into them. The riffles create eddies in the water as it moves towards the edge of the pan that will catch the fine gold so it doesn't wash over the lip. Of course if the water is moving too fast or the pan is tipped steeply everything can wash away, including the Gold! Patience, patience, patience! Practice, practice, practice!