Can You Grind Seashells Into a Mold?

Tabby

• Seashells have been used as a building material at least as far back as the earliest Spanish settlers in the southeast U.S. coast, who mixed crushed oyster shells with lime and sand to form a substance called "tabby." They poured and tamped this material into forms to create walls for permanent structures.

In the Kitchen

• Concrete countertops are popular in contemporary homes. According to the Concrete Network, the countertops are made by mixing cement, lightweight aggregates such as small stones, pieces of glass or shells, and additives such as fiber reinforcements in a custom mold built to the countertop's specifications. To make the finish called terrazzo, countertop surfaces are ground down to reveal bits of the individual pieces included in the mix.

Aquarium Accessories

• Some enterprising aquarium suppliers create their own live rock by making molds in wet beach sand, pushing decorative rocks and shells into the bottom of the mold and finally pouring in a mixture of aragonite (an aquarium sand) and Portland cement. After 24 hours, they remove the new rock from the mold and cure it underwater for 24 hours. The shell pieces remain on the outside of the new rock.

Bricks and Mortar

• An old recipe for handmade brick, revived by a South Carolina brick company, includes ground-up seashells in a mortar mix that is bright white, which is preferred by many customers because it is similar to mortar used 200 years ago in the region.