Chondrite meteorites can be split into groups based on the chondrules present. As the name implies, carbonaceous chondrites formed with chondrules and carbon. Chondrites are undifferentiated and have round mineral inclusions called chondrules. Chondrules and maskelynite are visible in thin section. Some of the melt droplets were incorporated into chondrites as small spherical objects called chondrules. Type 1 meteorites normally have no recognizable chondrules. Examples of embedded elements in cosmic dust are GEMS, chondrules, and CAIs. Minerals of this type include olivine and pyroxene, which are found in CM chondrules. More chondrules appear, leaving less matrix. Such chondrules are called "Type II". An achondrite is a stony meteorite that does not contain chondrules. Very characteristic are relic chondrules and chemical compositions close to the composition of chondrites. Some stone meteoroids contain grain-like inclusions known as chondrules and are called chondrites. Manganese-chromium dating of chondrules revealed an age of 4,571 Mya. Other non-metallic meteorites, achondrites, which lack chondrules, were formed more recently.