Tellurium is a metallic, silvery-white element. Some even describe its appearance as "very metallic." Its atomic number is 52 and its symbol is Te. It was discovered in 1783 by Baron Franz Joseph Muller von Reichenstein of Romania, the chief inspector of mines in Transylvania at the time. Tellurium is very brittle and easily pulverized. It does not react with air or water.

As a commodity, tellurium is used in industry as pure tellurium metal, tellurium dioxide (TeO₂), and alloyed (that is, mixed) with other metals.

Tellurium has no known benefit to humans. It does have a strange effect on humans, though. When tellurium is ingested, even in very small amounts, it causes very bad, garlic-smelling breath and body odor.

There are a very small number of tellurium minerals. It combines with oxygen to form tellurite, and with gold and silver to form sylvanite (Au,Ag)Te₂. The most common gold telluride mineral is called calaverite(AuTe₂).

The name tellurium came from the Latin word tellus meaning earth.

Tellurium is recovered from the residue produced in refining blister copper from deposits containing recoverable amounts of tellurium. There are large quantities of tellurium in some gold and lead deposits, but the tellurium is not being recovered from these at this time. In addition, tellurium is present in coal and some lower-grade copper deposits, but the cost of recovering the tellurium from these deposits is too high to make it worth the effort. These deposits are called subeconomic deposits.

Nations producing tellurium and tellurium dioxide are the United States, Canada, Japan, Peru, and a number of other countries. As with most commodities, companies in the United States import tellurium. Of the tellurium imported each year, most comes from the United Kingdom, followed by Philippines, Belgium, Canada, and a number of other nations.

Half of the tellurium consumed each year is used to improve the machinability of special iron and steel products. It is alloyed with copper to make copper more ductile (that is, easier to stretch into wires), and with lead to prevent corrosion. These, and other nonferrous tellurium alloys, account for approximately 10% of tellurium use. Tellurium is also used to make catalysts and chemicals. Some of these chemicals are used in the petroleum industry and in making rubber. Tellurium is added to selenium-based photoreceptors to broaden the spectral range of copiers. Tellurium is also used in other electronic applications, and in the production of blasting caps for explosives.

Selenium, bismuth and lead can be used in place of tellurium in many of its metallurgical uses. Selenium and sulfur can be used in place of tellurium in the production of rubber.