Bismuth or BI is atomic number 31 on the periodic table of elements under the poor metals category. It is a brittle metal often occurring in its native form with an iridescent oxide tarnish showing many refractive colors from yellow to blue. This is an example of a lab grown specimen grown from the melt at 520 degrees Fahrenheit and forming a trigonal (or rhombohedral) crystal system. These amazingly colorful specimen can range from rainbow to iridescent blues and purples.Do not place near pyrite as it may discolor. All minerals and stones vary in size and shape. You will receive a high quality specimen of the selected item but not the exact one pictured. All minerals, gems, stones and fossils are guaranteed to be top quality; sourced from ethical vendors around the world.