Selenium was discovered in 1817 by the Swedish chemist Jöns Jacob Berzelius.

Its name originates from “Selene,” the Greek goddess of the moon.

Selenium is a nonmetal, yet it exhibits metallic behavior in many circumstances.

It is positioned directly between sulfur and tellurium on the periodic table.

Selenium can exist in several forms, displaying red, black, and gray colors, and even a metallic appearance.

It is renowned for its photoconductivity, meaning its electrical conductivity increases when exposed to light.

Selenium was once utilized in light meters for early cameras.

Its conductivity changes so reliably with light that it contributed to the development of early photocopiers.

Selenium is essential for the human thyroid gland. Insufficient selenium causes health problems, but excessive amounts are toxic.

Brazil nuts represent one of the richest natural sources of selenium.

Selenium is employed to decolorize glass by neutralizing greenish tints. However, it is also used to impart a red color to glass, demonstrating its versatility as a pigment.

Selenium compounds can produce a deep ruby-red color in glass and ceramics.

Thin selenium coatings are utilized in the production of solar cells.

Selenium aids in protecting the body from damage caused by heavy metals.

It is used to fabricate rectifiers, which are devices that convert alternating current to direct current.

Selenium played a critical role in early radio technology.

Selenium is used in steel production to enhance machinability.

It is added in trace quantities to rubber to prevent cracking.

It was historically used in photovoltaic cells, particularly before silicon became dominant.

Selenium dioxide was a component in toners for photocopiers.

Selenium compounds assist in controlling dandruff in shampoos such as Selsun Blue but not Head & Shoulders.

Excessive selenium intake can cause a garlic-like odor on the breath, a condition known as selenosis.