Bismuth Crystal with Iridescent Oxide

Above: Front of specimen card.   "The Philosopher takes pleasure in the contemplation of the nature of these compounds while the miner takes pleasure in the profit and use he obtains from the metals he extracts from them." ~ Georgius Agricola, 1546 This specimen is a complete bismuth crystal. They are hand cast in Colorado by a family that specializes in creating bismuth crystals for the jewelry industry. We loved them so much that we had to share them with you. Above: A pair of Bismuth crystals in hand. A classic piece for every natural history collection, Bismuth, element 83, is known best for its multicolor formations of a deep, staircase-like structure. These fractal patterns are known as hopper crystals, identifiable by their hollow step lattices. When bismuth cools it forms in a rhombohedral structure with the edges of the formation crystallizing at a much faster rate than the center of the faces. This pulls material away from the interior and leaves gaps in the structure, causing the final product to appear hollow.  Above: Close-up of a specimen displaying the intricate lattice pattern. The crystal’s uniquely iridescent shine also occurs during its formation process. While the metal’s true color is a white silver, it can oxidize during the cooling process to form a thin layer of film. Above: A pure Bismuth ingot. We've used this material to make some of our bismuth crystals and it is a fun challenge! This film interferes with light waves, giving bismuth its colorful appearance, similar in process to the rainbow glimmer of a soap bubble. While these formations do not appear often in nature, bismuth’s relatively low melting point of 520 °F means it is possible to create synthetic bismuth crystals at home with the right materials. Above: A selection of Bismuth crystals As you can see, each crystal is a unique and beautiful natural art object. No two will be alike. The specimen is contained inside an acrylic specimen jar. The jar is enclosed inside a classic, glass-topped riker display case measuring 4 1/2" x 3 1/2". A small information card is also included. Please Note: This specimen is 100% safe to handle. While it can be used as a replacement for lead or as a pigment in cosmetics, Bismuth is most commonly used for medicinal purposes in the compound bismuth subsalicylate, known under the brand name Pepto-Bismol. It is not well understood how bismuth subsalicylate operates when ingested, but it is thought that it stimulates the absorption of fluid and electrolytes within the intestine while inhibiting inflammations. Long thought to have been the heaviest nonradioactive element, researchers in 2003 discovered that the naturally occurring isotope of the bismuth did in fact undergo alpha decay and calculated a half-life of 1.9×10^19 years. Luckily, this half-life is about a billion times longer than the current age of the universe, meaning that you won’t have to worry about any radioactivity from Pepto-Bismol or this specimen. 😎 Further Reading: Agricola, Georgius. De Natura Fossilium (Textbook of Mineralogy). Geological Society of America, 1955. de Marcillac, P., Coron, N., Dambier, G. et al. Experimental detection of α-particles from the radioactive decay of natural bismuth. Nature 422, 876–878 (2003)  Above: Back of specimen card.