That is, if you observe the spectrum of a star and can determine the wavelength where the emission peaks (Î»max), you can calculate that starâs temperature. Here is another copy of the plot that we studied in Lesson 3: Figure 4.1: Two-dimensional plot of the spectrum of a blackbody with different temperatures.
Igneous rocks usually contain the most crystals. The longer it takes the magma to cool, the larger the crystals.
Types of Rocks. There are three main types of rocks - igneous, sedimentary, and metamorphic. Igneous rocks are formed when melted rock (magma) cools and solidifies. Some igneous rocks are formed when the magma erupts from a volcano. Obsidian, basalt, and granite are all examples of igneous rocks.