Fig. 3: CCHH on the surface of coral skeleton and nacre, not on sea urchin spine.

A Myriad Map (MM) of coral skeleton from the smooth cauliflower coral Stylophora pistillata. B MM of nacre from the California red abalone Haliotis rufescens. C MM of sea urchin spine from the California purple sea urchin Strongylocentrotus purpuratus. All biominerals are observed in cross-section. The boxes in panels 1 indicate the regions magnified in panels 2 and 3. For all biominerals, the background is a grayscale photoelectron image of the area; the superimposed colored pixels are MMs obtained using 5 component spectra (Fig. 2C, Supplementary Fig. 1). Colored pixels in all panels represent pixels containing more than 50% of the indicated mineral phase, and are color coded according to the color legend in A1. For clarity, blue pixels of aragonite (for coral and nacre) and calcite (for sea urchin spine) are omitted from all panels. They are included in Supplementary Figs. 4–6, where all phases are displayed for all pixels in the first and second acquisition. All three areas were analyzed in duplicate with consistent results.