Gadolinium

Discovered by Jean de Marignac in 1880, gadolinium is named after the mineral gadolinite and also the Finnish meteorologist Johan Gadolin. It is never found free in nature- instead, it is found in other elements like monazite and bastnasite.

 Unlike most rare earth elements, it is very stable in dry air. However, it does tarnish quickly if exposed to moist air, as it reacts slowly with moisture and water. It also dissolves in dilute acid.

Gadolinium is not cheap- it is $485 per kilogram for the soft white metal! It is used in products such as microwaves, tvs, neutron radiography, and other items of lesser importance, such as computer memory chips and alloys and compounds. However, the price of gadolinium has dropped over the years as new technologies have been developed... like everything else, it is re-produced using different elements and chemicals, and has lost its value. It can now be prepared through reducing anhydrous fluoride with metallic calcium.