Jasper, an opaque form of quartz that contains iron oxide or iron hydroxide as an impurity. Jasper is usually red, brown, grayish green, or yellow. The stone is very hard and takes a high polish. It is used for inlays and for such ornamental objects as vases and decorative table tops. Showy or unusual forms of jasper are often used in jewelry. Ribbon, or riband, jasper is jasper in striped layers, or banded with rock crystal. Porcelain jasper is porcellanite, a dense, siliceous rock resembling unglazed porcelain. Brown or yellow jasper, also called Egyptian jasper, is usually streaked or clouded. Jasper occurs abundantly in veins and masses in many parts of the world.
Emperor Qin ordered 7,000 generals, cavalrymen and archers to protect his mausoleum. What's so odd about that? Well, they were made of terracotta.
Carbon-14 dating is something that you hear about in the news all the time. Everything from mastodons to the Shroud of Turin has been dated using this technique! Learn about how carbon-14 dating works and why it is so accurate!