Rhyolite

Rhyolite is a silica rich volcanic rock which many popular stones are types of rhyolite or associated with rhyolite. Some rhyolite erupts as a sticky thick dome while other rhyolite erupts as a airborne powder and forms a rock when it hits the ground and sticks to more ash and other things. 

Wonderstone - a welded glassy tuff which gets its cool patterns and extra hardness from groundwater oxidizing the stone and providing extra silica. 

Birdseye Rhyolite - rhyolite with bullseye patterns within it

Butterfly or Mariposa Jasper - colorful thunderegg formation where the thunderegg is as pretty as the filing so the whole stone is used. Mined in Nayarit, Mexico

Rainforest or Lilypad Jasper - small thundereggs still within their rhyolite matrix

Spiderweb Jasper - rhyolite with spheres creating large often multicolored dots in the stone

Kambaba Jasper - an altered rhyolite often confused as a stromatolite

Ocean Jasper - an altered silica rich rhyolite which has been exposed to extreme amounts of silica and now grows quartz crystals. 

Orbicular or Poppy Jasper - rhyolite which has grown spherulites creating a dotted pattern