Figure 8.00. The earth's moon from northern Vermont, March 2018. The light colored crust of the moon is made of anorthosite, consisting principally of plagioclase feldspar. The plagioclase is believed to have floated to the surface of a lunar magma ocean shortly after the moon formed. The bright moon is, therefore, a visible consquence of fractional crystallization. The anorthosite crust is pock-marked with meteorite impact craters of many sizes. The large ones were subsequently filled with dark basalt. Zoom and pan with your mouse or mousepad to look more closely or visit NASA Moon. John Brady photo.