Hafnon is a hafnium nesosilicate mineral with the idealized chemical formula . It is the mineral form of hafnium silicate and one of the few known minerals with essential hafnium.
Hafnon forms a solid-solution series with its zirconium counterpart, zircon (). Several other variants exist, with compositions such as . In nature, part of zirconium is replaced by the chemically similar hafnium, so natural zircon is never pure . However, a zircon with 100% hafnium substitution can be synthesized and is known as hafnon.
Hafnon occurs as transparent red to red-orange tetragonal crystals, with a Moh's hardness of 7.5.
Hafnon occurs naturally in tantalum-bearing granite pegmatites in Zambezia (Mozambique), and in weathered pegmatites at Mount Holland, Western Australia. It has also been reported at locations in Ontario, Quebec, and Manitoba, Canada; North Carolina, United States, and Zimbabwe.