Orbicular Jasper

Orbicular jasper is an altered rhyolite which has spheres or dots in it. In highly silicified rhyolite tuffs the quartz and feldspar crystals create radiating structures. These are known as spherulites. 

Depending on the amount if silica and how long the rhyolite is exposed, will dictate how hard, translucent and crystalline the alteration is. 

This type of jasper occurs in many places and is often a small local deposit with no name. 

Well known orbicular jaspers include: 

Morgan Hill Poppy Jasper - A spotted jasper from Morgan Hill, California USA south of San Francisco

Olympic Peninsula Poppy Jasper - No motherload has been found for this typically green and red poppy jasper found all over NW Washington, USA. 

Ocean Jasper - Mined by The Gem Shop in a remote region of Madagascar this orbicular jasper can have a lot of agate, chalcedony and quartz crystals present.