I have been experimenting with gold, black sand, and magnets for many years. Magnetic black sand particles will be attracted to one another and pinch particles of gold between them. This is why you can pick up magnetic black sand with a magnet, drop it in a pan, and find gold in it. This is true whether the black sand is wet or bone dry. When panning, you will often see gold particles sitting on top of black sand even though the gold is heavier. This is because the weight of the gold is not enough to overcome to force of the black sand particles being held together by magnetic attraction. The Cleangold(tm) sluice and other similar devices utilize an external magnetic force applied to the magnetic black sand particles to create a ”carpet” of black sand to catch the gold. Rarely, particles of gold will be cemented in magnetic black sand and picked up with a magnet. The gold can usually be separated from the clumps of black sand by roasting, tumbling, or use of a stamp mill. Pure or high fineness gold by itself is not magnetic, at least for practical purposes, unless a part of the alloying constituents are magnetic.