Colored and coated plateletlike pigments

DETAILED DESCRIPTION What is claimed is: 1.
A platelet-shaped pigment, consisting essentially of an inorganic, platelet-shaped matrix containing silicon dioxide, a silicate, boron oxide, a borate, an aluminate or a mixture thereof, and optionally containing carbon black, coated with one or more thin, transparent or semi-transparent reflective layers of metal oxides selected from titanium dioxide, zirconium dioxide, zinc oxide, iron (III) oxide, chromium oxide or mixtures thereof which give the pigment an interference color effect, prepared by: applying a liquid precursor of the matrix to a continuous belt as a thin film, solidifying the liquid film by drying, separating the resulting layer from the belt as particles and treating them with a mineral acid and washing them, suspending the particles in water and coating them with one or more reflective layers of the metal oxides.
2.
The pigment of claim 1, wherein the particles are dried, calcined, ground and classified before suspending them in water and coating them with one or more reflective layers of metal oxides.
3.
The pigment of claim 1, comprising a reflective layer consisting of chromium oxide, titanium dioxide, iron (III) oxide or a mixture thereof, giving the pigment an interference color effect.
4.
A process for preparing a platelet-shaped pigment of claim 1 having high luster and high covering power or high transparency, said process comprising: applying a liquid precursor of the matrix to a continuous belt as a thin film, solidifying the liquid film by drying, separating the resulting layer from the belt as particles and treating them with a mineral acid and washing them, suspending the particles in water and coating them with one or more reflective layers of metal oxides.
5.
The process of claim 4, wherein the liquid precursor comprises a silicate, a borate, a chloride, an aluminate or a poly- or metaphosphate of a metal selected from silicon, potassium or sodium, or a mixture thereof.
6.
The process of claim 5, wherein the liquid precursor comprises sodium silicate