Craters, old and young pockmark the surface of Mercury. the youngest craters on Mercury are bright. They are surrounded by material thrown out by the force of the meteorite impact. Inter- crater plains lie between the main craters of Mercury. Inter-crater plains are older, smoother areas dotted with small craters.
Secondary craters are caused by the debris from the main meteorite impact. The secondary craters of Mercury lie closer to the main craters than on the Moon, because of Mercury's stronger gravity.
Caloris Basin is the largest one among the craters on Mercury. It resembles the maria areas of the Moon. there are no known volcanic craters on Mercury.