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.
Rock crystal is only one of several quartz varieties. Other varieties that form macroscopic (large enough to see) crystals are as follows: 1  Amethyst is the purple gemstone variety. 2  Citrine is a yellow to orange gemstone variety that is rare in nature but is often created by heating Amethyst.ock Crystal is the name given to all clear colorless quartz. It is widely used as a popular ornamental stone and is also used as a gemstone. Although it is one of the least expensive gemstones, cut rock crystal has been used as imitation diamonds.