Thorium is used in a wide array of products and processes, for example in the production of ceramics, carbon arc lamps, strong alloys, and in mantles for lanterns.  It also is used as a coating for Tungsten welding rods, because it provides a hotter arc.  Thorium is added when making refractive glass, allowing for smaller and more accurate camera lenses, and also acts as a catalyst for the oxidation of ammonia to nitric acid.

Thorium's special properties make it useful when light or high temperature are involved.  The metal burns with a brilliant white flame and its oxide has the highest melting point of all oxides.  Although it was discovered in 1828, it had virtually no uses until the invention of the lantern mantle in 1885.

A sampling of its current uses are:

• Thorium is combined with magnesium alloys and in Tungsten filaments for light bulbs and in electronic tubes.
• Ceramic items, such as lab crucibles, become more heat resistant by adding Thorium.
• Makes carbon arc-light lamps burn brighter.
• Added to bulb filaments, it helps sun lamps mimic the light emitted from the sun.
• Makes Tungsten welding electrodes burn hotter.
• Forms strong but less brittle alloys.
• Thoria - Thorium oxide (ThO₂) is added to help gas mantles burn hotter and brighter.
• Added to make high refractive glass, camera and binocular lenses. See NCRP Report No. 95 "Radiation Exposure of the U.S. Population from Consumer Products and Miscellaneous Sources," section 3.2.8.3 (page 47)
• A catalyst for the oxidation of ammonia to nitric acid and other industrial chemical reactions.
• One of the breeded reactor fuels (see the Thorium Fuel Cycle)
• Used to date very old materials, e.g. seabeds or mountain ranges.