Feldspar: Fillers with high chemical resistance

With a proportion of almost 60 % by weight of the accessible structure of the earth’s crust, feldspars are by far the most frequent group of minerals. Feldspar is a chemically resistant tectosilicate with a thick-slated grain morphology. HPF offers potash as well as sodium feldspars which are processed and separated by an elaborate screening technique, then classified and micro-ground.

Nepheline syenite: a silica-free mineral

Nepheline syenite consists of feldspars and feldspar-type minerals such as albite, microcline and nepheline. This mineral raw material contains no crystalline silica. Exactly as feldspar, nepheline syenite is inert and is characterized by a Mohs hardness of 6, and a high degree of whiteness. HPF only offers surface-treated types.


  • hardness 6 (Mohs)

  • density 2.6 g/cm³

  • thick-slated structure

  • high chemical resistance

  • high degree of whiteness

  • low refraction index of 1.53 – 1.55

  • transparent behaviour in many binder systems

Main applications

  • dispersion paints as well as silicate paints and plasters

  • clear lacquer systems, i.e. UV-hardening lacquer systems

  • anti blocking in plastic films

  • dental

High Performance Fillers based on feldspar and nepheline syenite: