The difference between unroasted pyrite and roasted pyrite

The wording of unroasted pyrite is used in export declaration to be in accordance with HS code, It refers to (FeS2、iron pyrite、pyrite or Ferro Sulphur）.Its HS code is 25020000, and its molecular formula is FeS2, It is kind of natural mineral, mainly used in the production of sulfuric acid.
Roasted pyrite, its HS code is 2601.2000. It refers to residue of pyrite after it is used to produce sulfuric acid, commonly known as sulfuric acid residue or red powder. It is generally used as iron ore and its main component is Fe2O3.