I forgot to add this earlier, but an easy and less costly way of doing mosaics, such as stepping stones, is to go to a thrift store buy colored glassware and break it into pieces, or craft stores sometimes have broken glass pieces. You can also use decorative glass beads/blobs, marbles, river pebbles, polished rocks, sea glass, ceramic tiles, slate...the possibilities are as endless as your imagination. Then go to a home improvement store, buy a plain stepping/patio stone (here is an example), get Liquid Nails Glue for outdoor projects, then go to the flooring center and get sanded grout (they usually have a variety of colors). Arrange your pieces on the stepping stone first, then generously glue them into place. Allow the glue to dry completely. Then apply your grout, making sure you get into all the nooks and crannies and let that dry. You're done.