|The Simple English Wiktionary has a definition for: scandium.|
Scandium is a metal in a group known as the transition metals. It is also a rare earth metal. What this means is that there is not very much scandium found in the earth. Because of this, the pure metal can be expensive. The pure metal is very reactive, and will react with other elements like oxygen. The metal turns from shiny to gray.
Scandium is not very dangerous because there is not much of it on Earth, so there is not enough of it to harm us. It does not have many uses. Its main use is perhaps as a component in Mercury-vapor lamps. Such lamps are used to light Stadiums.