AbstractStoichiometric chrysotile tubular nanocrystals have been synthesized as possible starting materials for applications toward nanotechnology, and as a standard reference sample for the investigation of the molecular interactions between chrysotile, the most utilized asbestos, and biological systems. Chrysotile nanocrystals have been synthesized under controlled hydrothermal conditions, and have been characterized by chemical, morphological, structural, spectroscopic and microcalorimetric analyses. They show a constant “cylinder‐in‐cylinder” morphology constituted by two or three concentric subunits. Each single nanocrystal has a tubular shape of about 49±1 nm in outer maximum diameter, and a hollow core of about 7±1 nm. Structural investigation carried out on an X‐ray powder pattern allowed to improve the structural model proposed for chrysotile mineral samples. Synthetic chrysotile crystallizes in the monoclinic Cc space group with a=0.5340(1) nm, b=0.9241(1) nm, and c=1.4689(2) nm, β=93.66(3)°.