Rainforest Rhyolite Jasper, also known as Agatized Rhyolite, Green Rhyolite and Spherulitic Rhyolite, is a rare type of rhyolitic lava, associated with volcanic activity. Trapped pockets of gas bubbles during a lava flow are filled with other material, such as Agate, Jasper, Crystal Quartz, during it's solidification.