Like many gems, amber is used to make jewelry and other decorations. But it's formed unlike any other gem. Amber is actually fossilized tree resin that's 40 million to 60 million years old! Readers learn how this unique gem forms through accessible science content, including fun fact boxes that add even more detail. Close-up photographs of amber in full color engage readers with the fossilization process, the discovery of amber, and what this beautiful, natural gem teaches scientists about Earth's past.