Tear off a piece of aluminum foil from the roll. The sheet should be a couple of inches larger than you want the stepping stone to be.
Lay the map or cut-out of Texas on one sheet of foil.
Trace the shape of Texas onto the foil. Do not press hard enough to poke through the foil. You are tracing to make an indention in the foil, not a mark.
Cut the shape out of the foil. Add an extra 2 inches to the entire edge of the state.
Fold up the extra edge.
Tear off more aluminum foil sheets. Line the inside and sides of the shape with the foil. Add two to four more layers. The mold needs to hold its shape and be sturdy. The amount of layers you need depends on how strong the foil is.
Mix the cement mix in a bowl or bucket. Lay the mold on a flat surface and slowly pour in the cement. Smooth the cement with a putty knife.
Allow it to dry for at least 24 hours. Check it several times during the first four hours to make sure it keeps its shape. If it starts to shift, add more foil to the outside to reinforce the mold.
Remove the foil and place the stone wherever you want. The cement turns a light gray when dry.