An inselberg or monadnock /məˈnædnɒk/ is an isolated rock hill, knob, ridge, or small mountain that rises abruptly from a gently sloping or virtually level surrounding plain.In southern and south-central Africa, a similar formation of granite is known as a koppie, an Afrikaans word ("little head") from the Dutch word kopje.If the inselberg is dome-shaped and formed from granite-gneiss, it can also be called a bornhardt, albeit not all bornhardts are inselbergs.