Though the full Moon sometimes looks very much like a wheel of bleu or Stilton cheese, it is actually covered with rocks, boulders, craters, and a layer of charcoal-colored soil. The charcoal-colored soil consists primarily of pulverized rocky and glassy fragments, and is up to several meters deep. Two main types of rock have been found on the moon: basalt, which is hardened lava, and breccia, which is soil and rock fragments that have melted together. Elements found in moon rocks include aluminum, calcium, iron, magnesium, titanium, potassium, and phosphorus. Unlike iron-rich Earth, the Moon appears not to have much metallic content.