The Etruscans prized it as highly as gold. The Greeks mythologised it as the tears of Apollos daughters, solidified when they cried for their dead brother Phaeton. The Romans considered a single piece worth more than a slave. Cultures stretching from Central America to the Far East, from the Mediterranean to Scandinavia, have used it both as a powerful medicine and as a medium for exquisite jewellery and works of fine art.

Scientists, too, value amber. Trapped within the translucent, usually gold-coloured substance are some of the most ancient examples of certain species known to science. The oldest ants, moths, bees, caterpillars, termites, mushrooms and pollen grains, dating back tens of millions of years, have been found in amber. And unlike ordinary fossils, which are relatively crude rock molds of prehistoric life forms, these specimens are often perfectly preserved, with the most delicate features intact.

Now entomologist David Grimaldi of New York Citys American Museum of Natural History has announced a find he calls "scientifically the most important of all amber fossils." Its three tiny flowers, probably from an oak tree, that date to the age of the dinosaurs, some 90 million years ago. That makes them the oldest intact flowers ever found in amber, and an important clue to the origin of the flowering plants that now dominate the earth.

Not bad for a substance thats essentially dried-up tree resin. The viscous stuff that eventually turns into amber comes from a variety of ancient trees, mostly conifers, including pines and extinct relatives of sequoias and cedars, but also some deciduous trees. It probably evolved, says Grimaldi, as a defense against wood-boring insects. "As it dripped down the bark," he explains, "it acted like flypaper and encapsulated them, hermetically sealing the trees wounds at the same time."

Eventually the trees and their stalactites of dried resin fell, some of them ending up buried in soft sediments at the bottom of still and shallow bodies of water. There, over millions of years, the molecules of resin gradually amalgamated into long, durable chains, creating a material remarkably like plastic: airtight, watertight, chemically inert.

Although wood-boring insects might have been its target, the resin would also trap anything else that happened to stumble into it, including small lizards and frogs. Bad luck for them, but extraordinary good fortune for evolutionary biologists. In one major deposit-a site in New Jersey whose location is closely guarded- Grimaldi and a team of volunteers have found nearly 100 previously unknown ancient species of plants and animals. These and other discoveries around the world have given scientists some important insights into the workings of natural selection-how, for example, insects and flowers helped guide each others evolution.

Other samples provide dramatic snapshots of prehistoric behaviour: mites hitchhiking on the back of sweat bees; a leaf beetle spitting out a stream of noxious bubbles in self-defense; spiders caught in the act of mating; a praying mantis attacked by ants; a spider finishing off a millipede.

As anybody who has seen Jurassic Park knows, plants and animals sealed in amber are a potential source of prehistoric DNA. Scientists have extracted genetic material from, among other things, a 17 million-year-old magnolia leaf, a 30 million-year-old termite and a 120 million-year-old weevil. Yet no serious biologist believes it will ever be possible to clone a dinosaur from a few bits of DNA. Whilst amber is an excellent preservative, it cant keep DNA from breaking down into fragments that may be scientifically interesting but are biologically inert. Thats one reason many researchers doubt the claims of California scientists who announced last year that they had managed to revive bacteria preserved in amber for 25 million years. For scientists, a piece of amber with nothing trapped inside is not so exciting. For artists and their patrons, however, it is an uncut gem.

According to Grimaldi, Stone Age artisans used amber found on beaches of the Baltic Sea 10,000 years ago to carve amulets, pendants and tiny figurines. Indeed, Baltic deposits were Western civilizations primary source of amber at least as far back as 1200 BC. The name notwithstanding, amber isnt always amber in color. It can also be milky white, red and even blue or green, more than 250 different shades in all, say researchers and artists have used just about every one of them. 

Amber was strongly associated with death in ancient times. "It was believed to serve as a ray of light for the dead person in the afterlife," says Faya Causey, a historian of ancient art at the National Gallery of Art in Washington. Many of the amber figurines carved during the classical period relate either to death or to fertility and rejuvenation. Amber may have been used by Egyptians in the mummification process, possibly because it is a powerful desiccant, or drying agent. It was also valued as a medicine. According to Pliny the Elder, Roman peasants used it to cure diseases of the neck and head. In the New World, the Maya burned it as incense to treat a variety of ailments.

By the time of the Renaissance, the Western world had largely abandoned the mystical and medicinal uses of amber. But the great amber deposits of the Baltic still had plenty of business: guilds of craftsmen produced an enormous variety of secular objects, from jewellery to furniture. Under the patronage of aristocrats, amber carving reached its height in Prussia in the 16th, 17th and 18th centuries, culminating in the mystery-shrouded Amber Room.

The romance isnt over yet. Amber jewellery is still being produced in prodigious quantities, and thanks to Jurassic Park, there is a new market in bug and animal bearing amber as well. The growing demand for such items has run up prices for larger specimens to thousands of dollars, creating a secondary, shadow market for amber forgeries. Careless consumers may find themselves owning very expensive chunks of yellow plastic. But buyers who deal with reputable stores can, for a modest price, experience firsthand the beauty and mystique of these golden treasures from the ancient past.