Seeking the origins of amber: amber is frequently faked; the real thing may have unexpected value.(BEHIND THE SCENES)

ON A may morning in the National Arboretum in Washington, D.C.Jorge Santiago-Blay ducks under the branches of a Norway spruce to admire a thick white scab of resin that has oozed from where a branch was lopped off Then, using a metal dental pick, he lifts a piece of crusty resin from a 15-foot-long streak under the floppy crown of an Oriental spruce.

Mornings like this make Santiago-Blay, 55, a biologist at Smithsonian's National Museum of Natural History, sound a bit, well, sappy "I feel so lucky to be doing this work," he says, "because it means going to some of the most beautiful places on earth."

The 446-acre arboretum is one of Santiago-Blay's favorite …