Marine organisms have a unique ability to produce complex composite structures at ambient temperature and pressure using inorganic materials found in nature such as calcium carbonate and organic material (e.g. proteins and polysaccharides) produced at the cellular level. Examples of such organisms range from molluscs with complex mineral shells [J. Aizenberg, G. Lambert, L. Addadi, S. Weiner, Adv. Mater. 8 (1996) 222: S. Aibeek. S. Weiner, L. Addadi, Chem. Euro. J. 2 (1996) 278] to single-celled algae with ornate mineral scales [R.N. Picnaar, in: A. Winter, W.G. Siesser (Eds.), Coccolithophores, Cambridge University Press, New York. 1994, p. 13]. Understanding the basic process of scale or shell formation is intrinsic to mimicking nature's biofabrication scheme. We isolated and fractionated the organic material from the scales of the coccolithophore algae, Pleurochrysis carterae. We analyzed by atomic force microscopy the effects that the extracted organic material has on a growing calcite crystal in situ.