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Diatom [1] cell walls are outstanding examples of natural hybrid materials and exhibit extraordinarily interesting mechanical and optical properties.[2] Their structure and composition continue to inspire a variety of biomimetic synthesis approaches.[3] Diatoms are preferred model organisms in silica biomineralization studies.[4] Their hierarchically structured cell walls contain amorphous silica as well as special biomolecules. Over the past decade, three different classes of such biomolecules have been identified: 1) the silaffins, highly post-translationally modified peptides/proteins;[5] 2) long-chain polyamines (LCPAs);[6] and 3) the highly acidic silacidins.[7] The zwitterionic silaffins self-assemble into supramolecular aggregates. The same was observed for LCPAs [8] provided a properly chosen counterion such as orthophosphate or pyrophosphate, or a negatively charged peptide such as silacidin is present. Both …