Ductility refers to the ability of gold to be drawn into thin sheets or wires without breaking. This property is crucial in dental restorations as it allows gold to be finely adapted and contoured to the cavity margins, ensuring a superior marginal adaptation. Better adaptation minimizes gaps between the restoration and tooth structure, reducing microleakage and improving the longevity and success of the restoration. While malleability also plays a role in shaping gold, ductility specifically enables precise contouring at margins.

Reference: Sturdevant's Art and Science of Operative Dentistry, 7th Edition.