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.
Especially in the case of higher grade metamorphism, crystals can grow in the rock that are considerably larger than the average grain size in the rock (garnets, staurolite). These large crystals are called porphyroblasts (from Greek blastos, to grow) in analogy to porphyric crystals in igneous rocks. The NAMING OF METAMORPHIC ROCKS: Is done by combining the most abundant minerals and the textural type into a name. E.g. Garnet Hornfels, Quartz-mica Schist.