Silicon was first discovered by Jons Jacob Berzelius in 1824, and is named after the Latin word for flint, "silex." It was named this because flint is one of the common forms of silica. It was discovered after heating potassium chips in a container made of silica, an extremely common compound of one silicon atom bonded to two oxygen atoms.
Silicon, due to both being common and its electron configuration, is found in a multitude of compounds, and those compounds often come in a variety of forms. Like other elements in its group, most notably carbon, it has four valence electrons in its outer shell, enabling it to form up to four single covalent bonds at once. Just as pure carbon is naturally found as graphite and diamond — two very different materials — pure silicon is found in two forms. Its amorphous solid generally appears as a dull brown powder, whereas its crystalline form has a gray luster.
Silicon is both the second most abundant element in the Earth's crust and the seventh most abundant in the universe. Silica is both the most common compound of silicon and the most common compound in the Earth's crust. Its most common form is in quartz crystals, but is also found in other forms.