Shell of an idea: Designers repurpose mollusk waste into concrete


In South Korea, design firm Newtab-22 is turning waste shells from seafood and aquaculture industries into a terrazzo-like material. 

Dubbed Sea Stone, the shells are ground and mixed with natural, patent-pending binders to create a material that can replace concrete in small products like tiles, table tops and vases. Shells contain calcium carbonate, or limestone, an ingredient in concrete.  

According to Newtab-22, seven million metric tonnes of waste shells are left over from seafood processing every year. “Even though some of the seashells have been recycled and used as fertilizers, the majority of them are being thrown into landfills or by the seaside,” Newtab-22 told “The discarded seashells, which are uncleaned or rotten, have not been cleared away at all and they have been piling up near the beach for a long time, thus causing odor pollution and polluting the surrounding land in the long run.” 

The design house has no plans to try and create a concrete substitute, however, because in all likelihood large amounts of heat would be required for the material to reach the strength required for building structures. “We do not want to harm the environment in the process or the outcome,” Hyein Choi, co-founder of Newtab-22. “If you put high energy and cost, it is highly possible to use Sea Stone as real cement. It is paradoxical and controversial, we think, as this leads to secondary pollution.”