Hafnon is a hafnium nesosilicate mineral, chemical formula (Hf,Zr)SiO4 or (Hf,Zr,Th,U,Y)SiO4.[2] In natural zircon ZrSiO4 part of the zirconium is replaced by the very similar hafnium and so natural zircon is never pure ZrSiO4. A zircon with 100% hafnium substitution can be made synthetically and is hafnon.

Hafnon occurs as transparent red to red orange tetragonal crystals with a hardness of 7.5.[3][4]

Hafnon occurs naturally in tantalum-bearing granite pegmatites in the Zambezia district, Mozambique and in weathered pegmatites at Mount Holland, Western Australia.[5] It has also been reported from locations in Ontario, Quebec and Manitoba, Canada; North Carolina, United States; and in Zimbabwe.[3]

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