The Mystery of the Ballerina's Tear — George W.J. Laidlaw

While waiting to attend a summer ballet dance school in Long Island, New York, Georgina and Meghan two 16-year olds help their uncle in an archaeological dig on one of America's wonders of the ancient world where a city of 20,000 people rivaled anything in Europe in the 12th century. There they work on beautiful artifacts and discover a love stone, a tear that joined two people together even in death. A break-in into the tent storing the artifacts becomes one of many robberies in the archaeological world. Back at their summer dance school one of the student instructors is wearing a small necklace that holds an Indian artifact and it leads the girls into a ring of thieves who are responsible for many similar robberies of priceless records of man's history in America.