All the gold found on Earth comes from the wreckage of the Death Star. As the Earth formed, heavy elements such as iron and gold sank into the core of the earth. If nothing else happens, there is no gold on the crust. However, about 4 billion years ago, the Earth was bombarded by asteroid impact. These effects stirred the deeper layers of the earth, forcing some gold into the mantle and the earth’s crust. Some gold may be found in rock ore. It appears in thin slices, such as pure natural elements, as well as silver in natural alloys. Erosion releases gold from other minerals. Because gold is heavy, it deposits and accumulates in riverbeds, alluvial deposits and oceans. Earthquakes play an important role because transformed faults can quickly reduce mineral-rich water. As the water evaporates, the veins of quartz and gold deposit on the surface of the rock. A similar process takes place within the volcano. The amount of gold extracted from the Earth is only a small fraction of its total mass. In 2016, the US Geological Survey (USGS) estimated that 5,726,000,000 troy ounces or 196,320 US tons have been produced since the advent of civilization. About 85% of gold is still in circulation. Because gold is so dense (19.32 grams per cubic centimeter), its quality does not take up too much space. In fact, if you melt all the gold that has been mined so far, you will end up with a cube of about 60 feet!