This is what I usually think of for jasper
Jasper is a form of quartz that is usually red, yellow, green or brown, or a mixture of these colors that when polished makes beautiful jewelry. The name means “speckled stone.” Like many minerals, Jasper forms from volcanic ash. Patterns arise during the consolidation process. Sometimes the original materials are fractured allowing other colorful minerals to fill in the gaps.
This is a jasper bowl from Russia late 19th century- all pics courtesy of Wikipedia
Jasper was popular in the ancient world because it breaks with a smooth surface and is easily refined. Weathering with time will create intensely colored pieces of jasper. Today sometimes the jasper is named for the region where it originates, such as Biggs jasper from Oregon and Bruneau jasper from the Bruneau River in Idaho. There’s also one called Llanddwyn Island jasper from Wales