Specialty aggregates are great design elements, and they add a lot of pizzazz to the terrazzo.
I go to the coast of New England to source oyster shells, which I crush and grade myself. This is the recycled waste from the seafood industry. Oyster shells are wonderfully variegated, and take a nice polish.
Crushed mother of pearl shells have the same gorgeous iridescence as the pearls themselves. They are the recycled waste from the cultured pearl industry.
Aluminum and brass “chaff” are sourced from the waste stream of industries that mill these metals to make their products. They are small bits of metal that catch the light and add visual interest. Aluminum chaff really pops against a black background. Brass and aluminum letters are another specialty option. They create custom surfaces that speak.
I have pulled a lot of mirrors out of the trash. I crush and sift them. In terrazzo, mirrors create a dazzling effect, much like feldspar that occurs in granite.
Venetian terrazzo consist of oversized aggregates—so called because the palazzos in Venice used these large aggregates, to handsome effect, in their floors. More grinding is required in the process.
All manner of minerals, such as geodes and fossils, can be inlaid in terrazzo. You can find some great items at your local gem and mineral show, and it won’t break the bank. Glass aggregates are abundant and are another recycled ingredient. Use them with a translucent matrix, and you can create giant “lenses” of whatever colors you choose.
There are other options, but the trick is to choose aggregates of a similar hardness, so that it all grinds evenly.