Go to a public mine in order to get the nuggets. There are such mines in Alaska near Nome, Caribou Creek, Eagle, and Chugach National Forest, among others. Take note that the cost of traveling and doing the actual mining makes the endeavor rather expensive. Gold prospecting is generally not something to do on a whim or half-heartedly.
Prospect in other areas of the world with gold mines like Australia. One Australian public mine is the Three Creeks Gold mine in New South Wales. It allows panning for gold and other precious items that may still be found in the area's rocks and creeks.
Research companies that refine gold like Gold Refiners Australia. After turning in your gold to them, let them know that you do not want them to be turned into bars but to remain in their nugget form.
Purchase Aqua Regia, or "royal water," if you want to refine the gold yourself. This may be done by going on-line to businesses like the Shor International Company. Care should be used when working with Aqua Regis. It's composed of hydrochloric acid and nitric acid, which are very caustic.
Melt your gold sample in a kiln. Using tongs, pour out the liquid into a pyrex container. Add nitric acid according to how much sample you have. If you have 10 ounces of metal, use 300 mL of nitric acid. Wait a few minutes and then add the hydrochloric acid. The container with get very hot as the reaction occurs. The acid will turn brown and fumes will be emitted. Wait at least on hour for the reaction to occur. It is best, however, to waiting overnight, so that the most gold can be extracted.
Place the acid into a bigger container, taking care to not remove any particles as this is the gold. Filter the solution using a Buchner funnel. The acid should be translucent green. If there's cloudiness, refilter. Add urea to a container of water. Then add this mixture to the gold solution. Heat some additional water in a pyrex container. Then take the water off the heat and add 1 ounce of Storm to every ounce of metal being refined. Storm is the name of just one gold precipitate you can use. No matter which you choose, follow the manufacturer's directions.
Add the precipitant and water mixture very slowly to the acid with the gold. Wait 30 minutes.
Test for the presence of gold to make certain that you don't trash any precious metal that may still be in the solution. This test is accomplished by using precious metal detection liquid. Place a stirring rod in the acid, remove, and touch the end of the rod onto a paper towel, making a small dot. Place a drop of detection liquid on the dot to see if it turns purple-brown or purple-black. If it does, add more precipitant and/or wait for the precipitant to work for a longer time. The color change means some gold is still in the solution.
Look at the liquid to see if it is yellow in color with brown particles at the bottom. If it is, then the solution is free of gold. Filter the solution and then rinse the gold with tap water by adding the water to the same container the gold is in. Stir and let the gold particles settle. Pour off the water carefully.
Rinse the gold 3 to 4 times in the manner mentioned in Step 4. Then rinse the solution with aqua ammonia. White fumes will be seen. Pour off the ammonia and add distilled water. Pour this water out, leaving the "mud" particles behind. Pour distilled water onto the gold and pour the mixture into a bigger pyrex container.
Let the mud settle and melt it using a torch in a Burno crucible. Your nugget should be about 999.5% pure since filtering was done throughtout the process and a torch was used to melt the gold.