The provided mix natural flat river pebbles are formed from a natural process. They often possess ribbonlike membranes and may also possess shiny crystals produced by minerals developing slowly with time on their surface. These pebbles are produced when magma cools and solidifies. Sometimes, the magma chills within the earth, and different times it comes onto the surface through volcanoes. When the rocks cool quickly, zero crystals are formed and our mix natural flat river pebbles look glasslike and shiny. Sometimes bubbles are blocked in the rock amid the cooling procedure, leaving tiny spaces and holes in the rock.