Pearls have been valued as a sign of wealth and status for thousands of years. In ancient Rome, women wore pearls to bed so that they would be reminded of their affluence immediately upon wakening, and in seventeenth century Britain, a law was passed that made personal adornment with pearls an exclusive privilege of those with royal blood. Though smooth and beautiful, pearls are actually an abnormal growth that develops when a grain of sand or other foreign object becomes lodged in the soft inner tissues of an oyster or other mollusk. The irritation caused by the object stimulates the emission of a substance called nacre, or mother-of-pearl, by the mollusk’s shell-secreting cells. Over time, the layers of nacre build up, resulting in a round, lustrous pearl. Due to the rarity of pearls in nature, most pearls sold commercially in modern times are cultured pearls, which develop from the controlled implantation of tiny beads of nacre inside young oysters.

© 1995-2019 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, software, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.
This website is maintained by our
Graphics & Web Programming Team
in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory.
Last modification: Monday, Jan 05, 2004 at 05:58 PM
Access Count Since September 19, 1995: 21847
Microscopes provided by:
Visit the Nikon website. Visit the Olympus Microscopy Resource Center website.