The icosahedron is the kinetically stable and the most frequently observed structure. Especially, Au13 icosahedron is a common structure can be found in many gold nanoparticles.
For example, a thiol-stabilized gold nanoparticle:
Au25(SEt)18.
The structures were obtained from the literature (A. S. Barnard, Accounts of Chemical Research, 2012, 45, 1688-1697).