Remove the paper insert from your stepping stone use it and trace the shape onto the paper side of shelf adhesive. Cut the shape out with scissors.
Grab your glass tile nippers and a piece of stained glass. With the nippers positioned like in the photo, nip random shapes, some smaller and some larger.
Continue cutting and placing pieces until you're happy with the design.
In a plastic container mix together your sand/topping mix and water. To prevent bubbles appearing on the surface you need a consistency that is somewhat thin. However, you don't want your cement to be too runny or it will seep under the glass and ruin the terrazzo effect.
Gently spoon your cement into the mold taking care not to shift the shelf liner and glass below. When your mold is about half full take it and carefully strike the bottom of the mold on your work top. This will help pop any bubbles that have formed around your glass pieces.Fill all of the way to the lip of the stepping stone mold and place somewhere flat to cure. Let the stepping stone dry at least 24 hours.
Remove stone from mold and clean up as necessary. Allow several days to fully cure before use.