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.
A hard stone, usually within the range of 7-9 on the Mohs scale agates are found in all colors of the rainbow, although green and blue are quite rare. Agate is a variety of chalcedony formed from layers of quartz which usually show varicolored bands. It usually occurs as rounded nodules or veins. Often tiny quartz crystals form within the stone and add to the beauty and uniqueness of individual stones. These crystals are called drusy (sometimes misspelled as druzy).