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.
Basically, all intrusive igneous rocks have large crystals. Because they are intrusive, they take a long time to cool down, and so there is a lot of time for crystal growth. â¦ That said, the biggest categories of intrusive igneous rocks are: Peridotite (ultramafic) Gabbro (mafic) Diorite (Intermediate) Granite (silicic/felsic) Granite is the most common one in the continental crust.