The most common natural method of concentration of gold is through the ancient action of hot fluid inside the Earth's crust. (Fluids deep in the crust are heated by the Earth's internal heat. As they move towards the surface they cool down.) The fluids moved through the rocks over a large area and "dissolved" the gold. When these fluids cooled or reacted with other rocks the dissolved gold precipitated (came out of the fluid) in cracks or fractures forming veins. If the fluids move over a large enough area, and dissolve the gold for a long enough period of time, gold can be concentrated in amounts in the parts per thousand or even greater. As well as gold, the fluids carried other dissolved minerals, such as quartz. This is why gold is often found with quartz. These are known as primary gold deposits and to extract the gold the rock containing the veins of gold has to be dug up (mined), crushed and processed. In Australia this concentration of gold took place in the Earth hundreds of millions of years ago in the eastern states, and thousands of millions of years ago in Western Australia. The rocks containing the gold veins have now been exposed on the surface and are eroding away. The gold that these rocks contained has been washed down into creeks to form alluvial gold deposits. Here, the gold is further concentrated by the action of water. Because gold is heavier than most of the material moved by a creek or river, it can become concentrated in hollows and trapped in the bed of the river. These are known as secondary gold deposits and they can be worked using a gold pan, cradle. From: http://www.ga.gov.au/education/minerals/goldcalc.html

Gold is just a basic chemical element. It comes from the earth itself.

The origin of gold, like every other element heavier than iron, is from the explosion of a Super Nova. On the other hand, it's not true that gold cannot be created from other elements, because it can be created using nuclear reactions and a relatively common isotope of mercury as a starting point. But it is prohibitively expensive to do so and you'd spend far more money making the gold than you would get selling the paltry amount you could manufacture.

I just saw on the History channel that yes they can and have made gold from other metals. It seems they put the metal in the core of a nuclear reactor for around 24 hours. The metal comes out as pure gold. The problem is it costs thousands of dollars to run the reactor for 24 hours but the yield is less than 1/20 ounce of gold.