Lunar anorthosite, which was first obtained by humans through the Apollo space missions, may appear in either a coarse or finely crystalline form. White in color and relatively reflective, large accumulations of anorthosite are what give the lunar highlands a light appearance to those viewing them from the Earth. These highlands are believed to represent the earliest crust of the moon, and anorthosite samples from them have been dated at more than 4 billion years old.