The majority of the island of Komodo and its surrounding islands are composed entirely of the volcanic rock known geologically as Rhyolite. The word rhyolite was derived from the Greek word `rhyx` which translates to 'streams of lava'. Rhyolite is an igneous rock with a high silica content. This gemstone is basically a type of granite, however Rhyolite cools from its molten state too quickly for crystals to form as they do in granite. Rhyolite is an opaque mossy green gemstone flecked with tans, browns, and occasional clear spots.