Hafnon
IMA 1974-018
Hafnon is a very rarely occurring mineral from the mineral class of " silicates and Germanates ". It crystallizes in the tetragonal crystal system having a chemical composition Hf [ SiO 4 ], and thus a hafnium silicate. Hafnon is also the only known mineral having hafnium as the principal component. Structurally Hafnon is one of the island silicates and is closely related to zirconium ( Zr [ SiO4 ] ).
Developed Hafnon euhedral to irregular crystals and fragments of glass to diamond-like luster on the surfaces. In its pure form Hafnon is colorless and transparent. However, by foreign admixtures he takes most of an orange-red to brownish- yellow color, the transparency decreases accordingly.
Etymology and history
Was first discovered Hafnon in various mineral samples from the pits " Moneia " and " Morro Conco " and in the Muiâne pegmatites at Alto Ligonha in Zambezia Province in Mozambique. Was first described in 1974 by JM Correia Neves mineral, JEL Nunes, T. G. Sahama who named it after the main ingredient hafnium, with the ending- on is intended to indicate the close relationship to the zircon.
Classification
Already in the outdated, but partly still in use 8th edition of the mineral classification by Strunz was one of Hafnon to the mineral class of " silicates and Germanates " and then to the Department of " island silicates ( nesosilicates ) " where he along with coffinite, Reidit, Thorite, thorogummite and zirconium, the " Zirkongruppe " with the system number. VIII/A.09 formed.
The 9th edition valid since 2001 and of the International Mineralogical Association (IMA ) used the Strunz'schen Mineral classification assigns the Hafnon also in the department of " island silicates ( nesosilicates ) ". However, this is further subdivided according to the possible presence of other anions and the coordination of the cations involved, so that the mineral according to its composition in the subsection " island silicates without other anions; Cations " is to find where it also together with coffinite, Stetindit, thorite, and zircon thorogummite the " in octahedral and usually greater coordination Zirkongruppe "with the system no. 9.AD.30 forms.
The mainly common in English-speaking classification of minerals according to Dana assigns the Hafnon in the department of " island silicates ". He is also in the " Zirkongruppe " with the system no. 51.05.02 within the subdivision: to find " island silicates SiO4 groups with cations in > coordination ".
Education and Locations
Hafnon forms in tantalum- containing and weathered granite pegmatites. Accompanying minerals albite, among others, anthophyllite, apatite, Bismoclit, Bartyt, beryl, CesstibtantitCookeit, potassium- feldspar, Ferrocolumbit, cassiterite, Kimrobinsonit, Manganotantalit, microlite, muscovite, phlogopite, quartz, Thorite, tourmaline and zircon may occur.
A rare mineral formation Hafnon could be detected only in a few localities, where so far (as of 2013) a little more than 10 localities as have been established. The surroundings of Alto Ligonha is the only known locality in Mozambique.
Other previously known localities are the Forrestania - Rubellite - pegmatites in the administrative area of the Yilgarn shire in Australia, the Tanco Mine in Manitoba and Leduc mine in the province of Quebec in Canada, Sidi Bou Othmane in the Moroccan province Rehamna that Bikita - pegmatite in the province of Masvingo in Zimbabwe and the Ray Mica Mine ( Wray Mine) on Hurricane Mountain in Burnsville (North Carolina) in the USA.
Crystal structure
Hafnon crystallizes isotypic with zirconium in the tetragonal crystal system in space group I41/amd ( Raumgruppen-Nr. 141) with the lattice parameters a = 6.57 Å and c = 5.96 Å and four formula units per unit cell.