A polyhedron
A cuboctahedron.
Image taken from Giovanni StrĂ¼ver's memoir Studi sulla Mineralogia Italiana - Pirite del Piemonte e dell'Elba, from the memories of the Royal Academy of Science of Turin, Series II, Volume XXVI, 1871.
©
The image belongs to the sections...:
From a note of Struver (1871) (3D geometry)
Uniform polyhedra and their duals (3D geometry)