The lunar highlands are elevated areas on the moon that were created by material that accumulated in layers from the ejecta of craters. The highlands are riddled with craters and the rocks found there are thought to be between 3.84 and 4.48 billion years old. These craters were formed by the intense bombardment on the moon in the early days of its existence.
The rocks found in the highlands are big and largely anorthosite. This means they are igneous and originate deep in the body of the moon. They form when lava cools over time and are made out of plagioclase feldspar, making the crystals of the rocks are glassy, brittle and nearly transparent. These rocks also have a very large amount of calcium.
The lunar highlands are visible from Earth. They are notable because they are lighter than the maria, which are relatively smooth and flat areas on the lunar surface. The highlands are called terrae, which is Latin for Earth. The word maria is plural for the word for sea. The light color of the highland rocks comes because of their anorthosite qualities. The maria are dark because they are mostly made from basalt, another igneous rock.