Virginia Tech
Virginia Polytechnic Institute: Greenhouse Dinosaur Extinction Theory
This comprehensive page discusses the Asteroid Impact vs. Volcano-Greenhouse dinosaur extinction debate. It was written by paleontologist, professor, and scientist Dr. Dewey McLean.
Smithsonian Institution
National Museum of Natural History: The Allure of Pearls
Exhibition of some of the first known gems to early humans, this collection of pearls includes several world famous precious stones.
Science Struck
Science Struck: Versatile Uses of Calcium Carbonate
Learn where calcium carbonate can be found and how it is used to support human health, in industry, agriculture, the environment, and in other ways.