The ‘quicksand’ is not sand, nor sticky. It is made of hundreds and hundreds of tiny plastic mostly flat, smooth, three cornered plastic pieces absolutely identical and half a cm wide. Corners rounded. Light orange red. A single ‘bit’ can stick to a fingertip like a tiny bit of paper, they are so light weight.
These tiny plastic ‘bits’ will not stick to other plastic or each other. They flow freely.
After play sessions and meticulous clean up, one or two of these tiny bits would turn up days later seemingly appearing out of nowhere. They are so small and so smooth that it is almost impossible to use them in a play session and not have a few escape, even when carefully used.

Sean.