It is also found in the form of mineral monazites which makes up only about 1.1 parts per million of the earth's crust. It is best separated from other rare earth's by ion-exchange or solvent extraction techniques. Ion exchange is a reversible chemical reaction between an insoluble solid and a solution during which ions may be interchanged.
Solvent extraction is a substance in which another substance is dissolved, forming a solution.
The anhydrous chloride of fluoride is then reduced with calcium to make the metal. Terbium is used in x-rays and in color televisions tubes. Its color is a silvery, white and it is in the group of Rare Earth metals. Its atomic weight is 158.9254.