Poppy Jasper is a metamorphic variety of silica-rich rock bands or spots of red, orange, yellow, white and black, likely formed by the metasomatic* alteration of vesicular volcanic rock. Dissolved silica and iron were carried through porous volcanic rock filling in the holes.
 
* Metasomatism is the chemical alteration of a rock by hydrothermal and other fluids. It is the replacement of one rock by another of different mineralogical and chemical composition. The minerals which compose the rocks are dissolved and new mineral formations are deposited in their place.