Tellurium is a chemical element wi seembol Te an atomic nummer 52. A brittle, mildly toxic, rare, siller-white metalloid which looks seemilar tae tin, tellurium is chemically relatit tae selenium an sulphur. It is occasionally foond in native furm, as elemental crystals. Tellurium is far mair common in the universe as a whole nor it is on Yird. Its extreme rarity in the Yird's crust, comparable tae that o platinum, is pairtly due tae its heich atomic nummer, but an aa due tae its furmation o a volatile hydride which caused the element tae be lost tae space as a gas durin the het nebular formation o the planet.