The main use of thorium has been in the preparation of the Welsbach mantle used for portable gas lights. These mantles glow with a dazzling light when heated in a gas flame. Thorium is a source of nuclear power. More energy is available for use from thorium in the minerals of the earth's crust that from both uranium and fossil fuels. Thorium fuel reserves represent a source of energy much greater than the known coal, oil and natural gas reserves.
Thorium metal is used as a stabilizing component of electronic tubes and in magnesium alloys.
Thorium oxide is used in light filaments, electrodes and glasses that have a high refractive index and low dispersion. Additionally, thorium oxide in used in high-quality lenses for cameras and scientific instruments. Bayer Corporation is a research-based company with major businesses in health care and life sciences, and chemicals.