Hafnon is a
hafnium silicate mineral, chemical formula (Hf,Zr)SiO
4 or (Hf,Zr,Th,U,Y)SiO
4. In natural
zircon ZrSiO
4 part of the
zirconium is replaced by the very similar hafnium and so natural zircon is never pure ZrSiO
4. A zircon with 100% hafnium substitution can be made synthetically and is hafnon.