Jasper is an aggregate quartz variety of opaque chalcedony. Its typical brown color is due to hematite or goethite impurities. It is often brightly colored or banded by impurity inclusions. It can be almost any color and is popular as beads, cabochons and tumbled stones. A silicon dioxide with inclusions of iron. Chert is a general term applied to a granular cryptocrystalline quartz of which Jasper is an example of. As early as 8000 BC the people of what are now England and France dug shafts up to 300 feet deep into layers of soft chalk to mine chert nodules. It was a precious commodity that early people traded and transported long distances. Chert is not found everywhere and these are some of the oldest mining operations ever discovered.