Plain concrete stepping-stones or terra-cotta pots make solid bases for mosaics. Broken china, bits of glass, stones, crystals, marbles ... let your imagination determine what material you use.
Wearing safety glasses and keeping material wrapped in heavy cloth to prevent scattering, use a hammer or tile pinchers to break your material into pieces. Wear rubber gloves and handle pieces carefully because edges will be sharp.
For this project, we used a concrete stepping-stone. First, immerse it in water to wet thoroughly. Prepare thin-set mortar in a bucket according to package directions. Consistency should be similar to slightly runny peanut butter. Using a notched trowel, spread a 1/4- to 1/2-inch layer of mortar onto part of the wet stone. (Mortar dries in about 15 minutes, so plan your design first and work in sections.)
Arrange pieces as desired, pressing them lightly into mortar. Add extra mortar as needed under pieces for an even surface. Repeat to cover stone, leaving gaps between pieces for grout. Clean excess mortar from the surface and let dry overnight.
Mix grout according to package directions. Scoop a large amount onto stone. Spread with a trowel or spatula, filling gaps and removing excess as you go. We also spread grout down sides of the stone.
Using a wet sponge, clean excess grout from the sides and top of stone. Wipe in all directions and rinse sponge often. Repeat, taking care not to remove too much grout from gaps. Let stone dry 24 to 48 hours, then buff with a soft cloth. Place in garden!