Titanium Dioxide
Titanium dioxide has remarkable optical properties, with a very high refractive index close to that of diamond. It is also a very stable compound and can be heated to over 2000 K before melting.
Titanium dioxide is the most used white pigment and provides whiteness and opacity for paints and coatings (including glazes), plastics and paper. It has many specialty uses. It is resistant to UV radiation and thus does not discolor over a long period of time and ultra pure and fine crystal titanium dioxide grades are being increasingly used for sun screens.
It is also being used in novel nanotechnology applications. Much smaller amounts of titanium dioxide are used as a semi-conductor and to catalyze the photodecomposition of water into hydrogen and oxygen. It also has a high dielectric constant and a high resistance and thus it is used to make capacitors.