Mackinawite ([Fe>>Ni)S]), greigite (NiS₂[Fe₄S₄]S₂Fe) and a tunnel manganite (CaMn₄O₈) similar in structure to hollandite were minerals that enabled the onset of chemosynthesis and, later, of oxygenic photosynthesis — the two events to make the greatest impact at the surface of our planet. The inorganic complexes contributing to the growth of such minerals — ([FeS₂Fe]4H₂O; [Fe₄S₄]²⁺/¹⁺; [Fe₃S₄]^1+/0; NiFe₅S₈, CaMn₄O₈ as well as HP₂O₇ ³⁻) — were later sequestered by small organic molecules (initially polypeptides or carboxylate groups) to become active centres of the enzyme precursors that initially catalyzed the primary reactions of energy conversion and nutrient cycling. Examples of such adventitious cooptions were to produce (i) pyrophosphate ‘eggs’ in successive main chain NH peptide nests; (ii) protoferredoxins as thiolated metal sulfide eggs in peptide nests; (iii) precursors to carbon monoxide dehydrogenase (CODH)/acetyl CoA synthetase (ACS) as a Nipeptide and a thiolated egg in a peptide nest and (iv) the precursor to the active centre of the OEC by periplasmic carboxylates and hydroxyls adjacent to RC II in a protocyanobacterium.