In the red boundary at the temple you go to with the merchant go to the to where all the boulders have to drop to and go to the south side of the room you'll see stones in the water you can skip across these stones by clicking on them and youll get into the topaz room
To get the emerald: go to the Haunted Woods (teleport to it if possible) then where the last boulder drops, you can go behind there (to the right) to go to a new screen where you'll find the emerald