“Placer” is the name given to gold (and other minerals) found in alluvial deposits of sand and gravel in modern or ancient stream beds that are near the surface when found. During the California Gold Rush, prospectors used shallow metal pans or water-tight Indian baskets with sloping sides to mine placer gold. After filling the pan with mud, sand, gravels, and a generous amount of water, the miner “swirled” the pan from side to side in a circular motion. Larger pebbles and other materials were removed by hand, and smaller particles were carefully rinsed away, while the heavier gold sank to the bottom. The work was slow and required experience and skill. An experienced panner could process ½ to ¾ of a cubic yard in 10 hours. Improvements to the gold pan included the rocker, which allowed small groups to increase the amount of gravels handled in a shift, and the larger sluice box or “Long Tom.” Over 64% of the gold produced in California has come from placer deposits.