Element 39 in our International Year of the Periodic Table series is yttrium. One of a number of elements discovered in the mines at Ytterby, Sweden, yttrium is found in camera lenses, some mock gemstones, and white LEDs.

Yttrium oxide can be added to glass to make it heat and shock resistant. The oxide was also used to make phosphors with europium which gave the red colour in old cathode ray tube televisions.

Because of the expense of some gemstones, there’s a market for cheaper simulations. Yttrium aluminium garnet is used to mimic some gemstones, including diamonds. However, its use in this application has decreased since the introduction of cubic zirconia for the same purpose. These days, it’s more commonly used as a material in various solid-state lasers. Finally, cerium-doped yttrium aluminium garnet can be used to coat blue LEDs and make them appear white.

Remember, you can keep track of all of the previous entries in this series on the site here, or on the Royal Society of Chemistry’s dedicated page.