Structural characterization of palygorskite used in historical Maya Blue using nanodiffraction

Palygorskite, mixed with indigo, was used in ancient time to produce Maya Blue, a hybrid pigment of unprecedented robustness and longevity. Palygorskite shows a huge structural heterogeneity, arising from the presence of two crystallographic phases of different symmetry, additional impurity phases, cation substitution, and phase intergrowth. Because of these, structural characterisation from powder diffraction data is extremely challenging. The objective of this proposal is to collect single-crystal data on nano-fibers of palygorskite and of Maya Blue reproductions in order to gain better insights into their respective structures.