amber, fossilized tree resin. Amber can vary in color from yellow to red to green and blue. The best commercial amber is transparent, but some varieties are cloudy. To be called amber, the resin must be several million years old; recently hardened resins are called copals.

The tree species that produced amber are now extinct. They included cedars and other conifers and broadleaved trees. The most famous source of the world's amber is the Baltic coast of Germany. Amber is also found off the coasts of Sicily and England and in Lebanon and Jordan and Myanmar (Burma). In the Western Hemisphere, there are rich deposits in the Dominican Republic, Mexico, and the state of New Jersey.

Amber is of interest both for its decorative value and for the ancient, once-living inclusions that it preserves. Capable of being highly polished, it is the oldest decorative substance known. It was familiar to Paleolithic peoples and to the Greeks and Romans, who used it extensively in jewelry. Pliny recounts several instances of its artistic uses. Amber is used in the manufacture of beads, amulets, mouthpieces, cigar and cigarette holders, pipes, and other small ornamental objects.

When rubbed with a cloth, amber becomes charged with static electricity; Thales was familiar with its electrical properties. When destructively distilled, amber yields acetic, butyric, valeric, and other acids; water; and hydrocarbons. Baltic amber also contains succinic acid and is often called succinite. An essential oil (amber oil) is obtained from amber.

Leaves, flowers, insects, and small animals are frequently found in amber. Older fossils trapped in this way often represent the sole specimen of an extinct species. The oldest known fossils of arthropods (see Arthropoda) are entombed in amber that dates from the Triassic period (230 million years ago). Especially rich beds of amber in Lebanon and New Jersey have yielded many Cretaceous species dating back as much as 135 million years. Because of amber's preservative qualities, the DNA of the specimens trapped inside is intact, affording scientists a unique opportunity to study the DNA of extinct species.

See D. Grimaldi, Amber: Window on the Past (1996); G. and R. Poinar, The Amber Forest (1999).

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