As the lava cools, large amounts of liquids and gases are given off. Some of these liquids and gases soak into the nearest rock, but most follow cracks, and deposit mineral matter along these cracks, forming a vein. The gold ends up as sediment in the bed of the stream or on its flood plain or delta and can be gathered by panning, dredging, and hydraulic mining. Gold is widely distributed on the earth and is even present in seawater. But, the cost of current methods for recovering it exceeds its value.
Most gold is retrieved in a metallic state in the form of dust, grains, flakes, or nuggets.
It is found, usually in association with silver or other metals, in quartz veins or lodes so finely disseminated that it is not visible. One of the rarest treasures found in the SS Central America wreckage is the collection of assay ingots. Miners would bring the gold dust and nuggets to an assayers office to be measured and melted down into ingots, or gold bars. These bars were marked with the name of the assay office, the weight, and the purity of the gold. For payment, the assayer would shave off a corner of the bar to keep for himself as well as to test the purity of the gold.