Figure 6-25 Anorthosite The lunar highlands are covered with this ancient type of rock, which is believed to be the material of the original lunar crust. This sample’s dimensions are 18 cm × 16 cm × 7 cm (7 in × 6 in × 3 in). Although this sample is medium gray, other anorthosites retrieved from the Moon have been white, while others are darker gray than this one. This rock was brought back by Apollo 16 astronauts.