Amber is fossilized(化石化された)tree resin(樹脂)that can vary in color from yellow, to red, to green and blue. Most of the world's amber is 30-90 million years old and was produced from tree species that are now extinct. It was familiar to Paleolithic(旧石器時代の)peoples and is the oldest decorative substance known. Because of amber's preservative qualities, the DNA of specimens sometimes found trapped inside it is intact(そっくりそのまま), affording scientists a unique opportunity to study extinct species.