Pieces fall from above (a bit like in tetris). Each piece is composed of a certain number of pre-colombian styled stone heads of a certain color. You can rotate the pieces and change their color arrangement too. Then you have it fall down where you want to make a match.
There are two play modes: Adventure or Arcade. I seem to remember that in Adventure mode you have a fixed time limit and a number of stones to break (by matching them), while in Arcade you have one challenge per level. For example, you must reach a certain amount of combinations (sometimes specific combos) to get to the next level.
OS: Windows XP/Vista/Win7
CPU: 1.2 GHz
RAM: 512 MB
Hard Drive: 10 MB