Calcite grain


Made in

Bioplastic 72 Composite 95 Alginate 8 Calcite grain 2 Gelatine 14 Glycerine 34 Vinegar 13

Calcite grain

Photos: Florian Geerken, Esmee Geerken, Inge van Dijk

Mineralized Matter & 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 out of the buildings of microscopic organisms, 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?

Esmee, 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. Esmee decided to give it a try. It appeared to be more difficult than she had anticipated.

In an earlier experiment, Esmee 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 slow, very slow, process.

Concrete, the building material most widely used, made from finite geological resources such a sand and limestone, is not very elegant: it’s brittle, prone to degradation and it’s 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, by listening and looking attentively at those surrounding us, by growing shelters from locally available materials, by recycling precious materials, by building with love and care for everyone, human, non-human, plant, bacteria, and everything, sand, shells and stones, by tuning into biogeochemical cycles,

The project BUILD LIKE A SHELL: CALCIFIERS AND AGGLUTINANTS explore these questions within a practice, hovering 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, Esmee started to play with calcite grains harvested from drinking water de-hardening, and bioplastics, forming a new exoskeleton like material.

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

This work is kindly sponsored by Aquaminerals and Stimuleringsfonds.

Additional information

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 your favourite bioplastic recipe on top of it (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 of the material and use it. You can also add the mixture to a piece of fabric, such as cotton.

Information submitted by the maker and edited by the Future Materials Bank.


Calcite grain, glycerine, vinegar, gelatine or alginate.


Aquaminerals, Stimuleringsfonds