In answer to your question, Toni, the multi-colored thing is called a "hyper cube" and it's created when you match five of the same colored gems.

When you move a hyper cube into another gem, it destroys all of the gems on the screen with the same color with a lightening bolt display.

Hyper cubes are valuable, because as long as you have one, you can't run out of moves.

Julia G.