👉 A selenite is a mineral that is composed of two distinct elements, selenide and selenium. Selenite is typically found in the rocks of the Earth's crust, where it forms from the oxidation of sulfuric acid in water or by exposure to sunlight. The term "selenium" refers to a chemical element with the symbol Se (also known as Selenium), which is also used for the color of its oxide. In the context of selenite, selenium is not typically identified