"Pearls have been valuable for thousands of years! They were known to Julius Caesar as well as worn by Native Americans centuries ago. In this book presented by Scientific America, readers learn how pearls are made, the difference between naturally formed pearls and cultured pearls, and even how to tell if a pearl is fake or real. Full-color images showcase the luster and beauty of pearls as the main content and interesting fact boxes highlight the geological, historical, and scientific studies of pearls. The main content supports knowledge building, a key component of the science of reading"-- Provided by publisher.