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.
Pegmatite containing lepidolite, tourmaline, and quartz from the White Elephant Mine in the Black Hills, South Dakota. A pegmatite is a holocrystalline, intrusive igneous rock composed of interlocking phaneritic crystals usually larger than 2.5 cm in size; such rocks are referred to as pegmatitic.Most pegmatites are composed of quartz, feldspar and mica, having a similar basic composition as granite.rystal size is the most striking feature of pegmatites, with crystals usually over 5 cm in size. Individual crystals over 10 metres across have been found, and many of the world's largest crystals were found within pegmatites. These include, spodumene, microcline, beryl, and tourmaline.