Magnesium (Mg) is a lightweight, silvery-white alkaline earth metal that is commonly found in nature, often in the form of minerals like dolomite and magnesite. Optically, magnesium is mostly utilized for its reflective properties. Its alloy forms, particularly with aluminum, are used to produce ultralight mirrors for astronomical instruments. Furthermore, these magnesium alloys are beneficial in the fabrication of mobile electronic devices, cameras, and lightweight vehicles due to their low density. In its pure form, magnesium is quite reactive, but the formation of an oxide layer on its surface helps protect it from further reactions in ambient conditions. Magnesium's potential for optical applications is limited but noteworthy in specific niches.