Match 3 jewels and gain point. You can also match more then 3 and get even greater score.
Click on two pieces to swap them. Swaps must create a matching set of three-in-a-row horizontally or vertically. Those pieces will be removed and new pieces will drop down to replace them. The game may end either by the time running out or no more possible matches.
A context menu should be shown when right-clicking or, on touch devices, long-pressing in the game. This menu especially allows to play in full screen and control the volume.