Here is a fantastic stromatolite specimen from the Precambrian of Australia. Authorities believe that stromatolites were formed by masses of green or blue-green algae. This extremely large (almost 11 inches long) stromatolite slab has been highly polished on both sides to reveal the beautiful colors of the mineral replacement. The reddish-black lines of hematite combined with the golden flashes of tigereye make for a very striking display. This is truly a beautiful slab of this colorful stromatolite from ''Down Under''.