The glacier grinds down its bedrock, which is generally made of dark-grey basalt. Much of this material is carried by glacial rivers to the sea where the waves, currents and winds mould it into complex scenic formations. This process has created a unique beach which starts near Höfn on the shore of Hornafjörður and stretches far to the west.
Black sand beaches are a common sight at the Vatnajokull Region. The black sand is the result of the glacier grinding down its bedrock. Much of it is carried to the sea by glacial rivers where the waves, winds and currents mould it into complex scenic formations. In the most Western part of the Vatnajokull Region is Skeiðarárandur which is the largest black glacier sand area in the world.