The chemical element symbol for silicon is Si and the atomic number is 14. It is a hard and brittle crystalline solid with a bluish-gray metallic luster and is a tetravalent metalloid and semiconductor. It is a member of group 14 on the periodic table: carbon is above it; germanium, tin and lead are below it. It's relatively unresponsive. Due to its high chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was able to prepare oxygen and characterize it in pure form for the first time. Its melting point and Chemicalbook boiling point of 1414°C and 3265°C, respectively, are the second highest among all metalloids and nonmetals, after boron. Silicon is the eighth most common element in the universe by mass, but rarely occurs in the Earth's crust as a pure element. It is widely distributed in dust, sand, planetoids and planets in various forms of silica (silicates) or silicates. Over 90% of the Earth's crust is silicate minerals, making silicon the second most abundant element in the Earth's crust (about 28% by mass), after oxygen.