A mineral so rare that it has only ever been discovered once in the world is capturing the attention of gemologists and scientists alike, Science Alert reports.
The mineral, known as kyawthuite (pronounced cha-too-ite), is a small, tawny-hued grain that weighs just 1.61 carats (approximately a third of a gram). At first glance, its appearance might remind one of amber or topaz, but its value and rarity make it far more extraordinary.
Kyawthuite was first purchased in 2010 by gemologist Kyaw Thu at a market in Chaung-gyi, Myanmar. Initially, he believed the raw stone to be scheelite, a mineral commonly found in the region. However, after cutting and polishing the gem, Thu realized that the stone exhibited unusual properties that did not match any known mineral.
Unable to identify the specimen, Thu sent the gem to the Gemological Institute of America (GIA) Laboratory in Bangkok, Thailand, where mineralogists made a groundbreaking discovery. The stone was found to be related to synthetic bismuth antimonate (BiSbO4), a compound that had never before been found in nature in this particular form. The unique chemical structure of the mineral, Bi3+Sb5+O4, is unlike any other naturally occurring substance.
At just 5.8 by 4.58 by 3 millimeters in size, the kyawthuite mineral is incredibly small but boasts a striking orange hue with a red overtone. When scratched across a rough surface, it leaves a white streak, a characteristic known as its “streak color.” The mineral also contains hollow, tube-shaped inclusions known as en echelon veins, which are formed under shear stress—an indicator of its natural formation.
Geologists speculate that kyawthuite likely formed in an igneous environment, possibly within a common volcanic rock called pegmatite, which is prevalent in the region where the mineral was found. Pegmatite is known for containing large crystals of various minerals, much like a “fruitcake” of geology, with different components jumbled together. The presence of elements such as titanium, niobium, tungsten, and uranium within the stone further supports the idea of its formation in pegmatite rock.
While the full circumstances behind the formation of kyawthuite remain a mystery, laboratory experiments suggest that bismuth antimonate crystals form under high-temperature conditions, similar to those in cooling magma. These rare and specific conditions likely explain why kyawthuite is so incredibly rare.
At present, kyawthuite holds a value that is considered priceless, given its uniqueness. In comparison, the world’s second-rarest mineral, painite, is valued at around $50,000 to $60,000 per carat. However, kyawthuite is far rarer, making it of immeasurable worth to both collectors and researchers.
Currently, the only known specimen of kyawthuite is safely housed at the Natural History Museum of Los Angeles County, where it remains a captivating example of the wonders of the natural world.
