Jasper is a form of crypto-crystalline quartz called chalcedony. Translucent chalcedony is called agate, opaque stones are called jasper. Jaspers are found in large deposits throughout the world and frequently have bright beautiful colors and patterns. They are usually cut into cabochons and most varieties are relatively inexpensive.
Color and pattern are important characteristic in determining a Jasper’s value. In most cases, the value of the stone will be substantially less than the value of the mounting.

Jasper is regularly dyed to generate different colors and patterns. The stone called black onyx, for example is almost always dyed agate.