In crash bandicoot warped how do you get the yellow gem?

Well you have to get about 15 reliques(the ones you price when you pass a world on a determinated time) then on the middle of the "warp"(the place where you chose in which world enter) will apear a stone, if you step that stone it will take you to another level with 5 worlds more, one of then is the danger zone where you get the yellow gem.

Sorry for my grammar but i´m from Mexico and i´m doing my best XD