Researchers have developed a novel technique to quantify the helical morphology of gold chiral nanorods. Such nanoparticles exhibit unique properties in a sense that they can change the circular polarization of light. In many cases, these properties are believed to be caused by the helical (or ‘screw-like’) morphology of the nanoparticles, but until now it was very difficult to objectively analyze their shape. This methodology is the first building block towards a fundamental understanding of the chiroptical activity of nanoparticles.