Maya blue is a pigment composed of indigo molecules (obtained from añil, Indigofera suffruticosa) encapsulated within the crystalline structure of palygorskite, a fibrous clay available in the Yucatán region. The combination produces a turquoise-blue color of extraordinary stability: it resists strong acids, organic solvents, extreme heat, and the passage of centuries without appreciable degradation. It was used extensively in sacrificial ceremonies, ceramics, murals, and the Sacred Cenote of Chichén Itzá. The exact synthesis process — including heating temperature and component ratios — was not deciphered by Western science until the 2000s using mass spectrometry and electron microscopy. Modern chemistry has identified the mechanism as a molecular intercalation that stabilizes indigo against oxidation, a principle now being investigated for applications in biotechnology and materials conservation.