Geological Chronicle
Piazzi is an impact crater spanning 102.57 kilometers in diameter near the southwestern limb of the Moon. Attached to the southeastern rim of the walled plain Lagrange and lying about three crater diameters north of Inghirami, Piazzi is seen at an oblique angle from Earth and appears oblong due to foreshortening.
The formation was heavily modified by ejecta from the formation of the Mare Orientale impact basin to the northwest. This material produced radial valleys and ridges across the surface of the crater. Piazzi's outer rim is irregular and eroded, while its uneven interior floor contains a few small craters and dark patches of low albedo along the northeastern rim.