Black sand deposits, which are composed of heavy metal materials such as iron and hematite, are common in areas where gold is found. While mining hobbyists typically regard the presence of black sand as an indicator of gold deposits, the sands themselves contain small particles of gold, called flour gold, and the sands are frequently processed for gold extraction. This processing requires screenings and the use of a strong industrial magnet that can be purchased at your local hardware store.
Dry the sand containing the fine gold, placing it into a metal pan and heating it using a portable hot plate. Use a medium heat for 15 to 20 minutes and perform the task in an outdoor area with good ventilation. Turn the heat off and allow the sand to cool.
Use a 6-inch-square piece of window screen to sift out the fine particles, placing the dried sand on the screen and shaking lightly over a small bowl. Place the materials that did not pass through the screen on a piece of paper and use tweezers to remove larger gold particles from the materials that were too large to pass through the screen.
Screen the fine materials again, using a kitchen strainer that has smaller mesh size than the window screen. Place the larger screenings on a fresh sheet of paper and remove any visible flakes of gold.
Place the fine materials that have passed through the two screenings on a sheet of paper. Pass a strong magnet over the sand to separate the remaining black sand. Black sand contains metal impurities that will stick to the magnet as it passes, leaving the flour gold on the paper. Remove the sands as they fill the magnet, repeating the process until the flour gold is all that remains on the paper.
Use a small funnel to transfer the processed flour gold into a small jar with a tight-fitting lid.