Devils Marbles - several circular shaped marbles of red granite are balanced on top of a hugh rock in last evening light. The whole rock formation is situated amidst grassy bushland . Devils Marbles Conservation Area, Northern Territory, Australia. The Devils Marbles; also called Karlu Karlu in indigenous language; is a spectacular formation of huge granite boulders spread across a wide shallow valley. They owe their creation to the circulation of day and night; respectively the very hot day temperatures and bitter cold desert nights. Because of those hugh differences in temperature; giant granite boulders expanded and shrinked in size continually. As a result the surfaces of these blocks flaked off like onion pellicles; and still does.