Sands of the Nile

Sands of the Nile, also known as Hindu Sands, is a stage illusion which was performed and made popular by Doug Henning.

Here is how Doug Henning's performance looked to those who saw it on TV. He would stand behind a small, high, table, bearing a large transparent bowl and three small piles of colored sand. He would begin by pouring ordinary-looking water into the bowl. As he began to tell a story about an ancient Egyptian ritual, he would stir the water with his bare hand, upon which it would turn black and opaque. As the story unfolded, he would then place a handful of each color of sand into the bowl of dark water, then extract them, one by one, dry and unmixed. Henning would then stir the water one last time, and it would again become completely clear, with a few stray grains of sand left in it.

Method

This is a classic item sold at magic shops. Here is one method that some have used to duplicate the magic shop item:

There is a product called magic sand (or "Wondersand" or "Space Sand"), that is, or at least was, available in almost any well-stocked toy store, science education supply house, and perhaps also in some science museum gift shops. It consists of dyed sand with a strongly hydrophobic coating. It may or may not have been originally developed as a way to sink oil spills; it is apparently also used to surround buried pipes in extremely cold climates; its water-repellent properties would allow the pipes to be dug up easily for maintenance. It was primarily marketed, though, as a children's toy, a material that could be poured into a container of water, and sculpted while underwater: once the water was poured off, the sculpture, held together by the surface tension of the surrounding water, would collapse.

Darkening the water at the beginning of the trick, then clearing it at the end, could be accomplished by a variety of methods, involving either dyes and bleaches, or a reversible (or even timed) chemical reaction. By using "magic sand," each handful of sand would remain dry under water, and would be held in an easily-retrieved clump by surface tension, so long as it remained underwater.

Clearly, the hardest part of such a trick is the presentation.