Smalti tile and dichroic glass center. The smalti came in an exchange with a lovely friend in Massachusetts. Smalti is the creme de la creme of glass tile, made from a secret formula guarded for thousands of years by the makers in Italy. The art on the ceilings and walls of the magnificent cathedrals in Europe were created with smalti. The center is dichroic glass ($101/lb., of which this is a tiny bit). The picture does not do it justice; it looks like a sun with multi-colored rays.
From the same exchange, this cross is made from blue and white Nordic saucers. I love many color combinations, but blue and white is something special.
All my garden stones are made using mortar (thinset) as the adhesive and as the grout, and are sealed front, sides, and back with Dupont stone sealer, so they should be good for many, many years as outdoor one-of-a-kind art pieces.