Calcite grain

Mineralised Matter and Organic Octahedrons

Limestone, the main component of cement, consists of the (microscopic) shells of marine biomineralising organisms, such as ‘foraminifera’ and ‘coccolithophores’. Over the past 500 million years, these shells have been sedimented onto the seafloor, compacted into limestone, and uplifted into cliffs and mountains.

Knowing that our buildings are made from microscopic organisms, designer Esmee Geerken started to wonder: what can we learn from these shell-forming organisms? How can we approach the ‘biomineralisation’ of our urban ecologies in a new, more sustainable way? Can we shortcut geological timescales by directly growing ‘seascrapers’ from seawater? Can we return to the proto-Indo-European roots of the word ‘building’: being, existing and growing, and re-learn how to build (be) like a shell?

Geerken who studied foraminifera during her PhD in biogeochemistry, started to dream of forming her own 'sites of calcification' – a term coined to describe the space in which biomineralising organisms form their shells. In this space, secluded from seawater and under tight biological control, organisms are able to grow minerals on top of an organic template, she decided to explore this process and it was more difficult than she had anticipated.

In an earlier experiment, Geerken and her co-authors discovered that foraminifera (whose shells are the building blocks of the pyramids in Egypt) secrete their shell walls at a speed of 0.5 micrometre/hour.

At this speed, it would take a year to form a kitchen tile of 0.5 cm. Unaided by geological timescales, and vast oceans full of mineralising organisms, growing calcite is a very slow process.

Concrete, the building material most widely used, made from finite geological resources such as sand and limestone, is not very elegant: it’s brittle, prone to degradation and its production amounts to 7% of global CO2 emissions. Our bodies do know how to make elegant materials: bones and shells are intrinsic composite materials of collagen and hydroxyapatite, both strong and flexible as well as sustainable.

Can we re-learn how to build interaction and harmony with our environment, by learning from foraminifera? By slowing down, listening and looking attentively at those surrounding us, growing shelters from locally available materials, recycling precious materials. Can we build with love and care for everyone, human, non-human, plant, bacteria?

The project 'Build Like a Shell: Calcifiers and Agglutinants' explores these questions. Moving between art, material design and earth sciences. Inspired by foraminifera, who build their shell by either mineralising an organic template, or by 'glueing' together sand particles collected from the sea floor. The designer has started to play with calcite grains harvested from drinking water de-hardening, and bioplastics, forming a new exoskeleton like material.

In the images, you see an 'agglutinating' foraminiferal specimen placed in a culture dish with glass pearls, that the specimen used to form new chambers. In the other images, you see (failed) experiments, attempts to grow calcite, as well as material studies with the calcite-grain material.

Making process

Add the calcite grains onto a smooth surface (glass, for example) or a sheet (optionally: a sheet with a texture), and pour a mix of bioplastic on top (various recipes to be found online, see for example the bioplastics cookbook, or look within the future materials bank). Leave it laying out flat for a couple of days to harden, then you can peel off the material and use it. You can also add the mixture to a piece of fabric, such as cotton.

Text submitted by the maker and edited by the Future Materials Bank. For information about reproducing (a part of) this text, please contact the maker.