It is found in the products of nuclear fission, and in mineral monzonites. The color of terbium is a silvery-gray. Terbium is a solid that is soft enough to cut with a knife and it is also malleable and ductile, this means that it can be easily molded and stretched. Little is known about the toxicity, but it should be handled with care. Terbuim is used in X-rays and in color TV tubes.
Terbium is used in color TV tubes.