Nature inspired synthesis of magnetite nanoparticle aggregates from natural berthierine.

We investigate the origin of the magnetite nanoparticle aggregates (MNAs) from the Peña Colorada iron-ore mining district (Mexico) to devise a nature inspired synthesis process. Three types of samples were used: natural MNAs recovered from the mine, concentrated magnetite microparticles as reference material, and thin berthierine films used to synthesize MNAs. The chemical, mineralogical, crystallographic and rock magnetic properties were determined by polarized microscopy, high-resolution transmission electron microscopy, electron microprobe, X-ray diffraction, Mössbauer spectroscopy, and thermomagnetic and hysteresis measurements.