Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny metal and the most malleable and ductile metal known. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a transition metal and a group 11 element. It is one of the least reactive solid chemical elements. The metal therefore occurs often in free elemental (native) form, as nuggets or grains in rocks, in veins and in alluvial deposits. Less commonly, it occurs in minerals as gold compounds, usually with tellurium. "Source: Wikipedia"
So what does all this mean? Heres a good quick summary. Gold is yellow and very shiny in most cases. It is over 18 times heavier than water. It takes the shortest path between bends in a creek (I'll post tips about reading a creek to find where gold would naturally deposit on another post). Oh yea, did I mention it was HEAVY? That's the key. A 1 ounce nugget wouldn't move down stream at flood stage compared to a 100 POUND boulder. Because the boulder has much more mass compared to the nugget even though it is much much heavier! Gold will eventually work it's way to the bottom (top of the bedrock in the bottom of the creek) unless it is on it's way down from the source (lode deposit).