Kyawthuite is a transparent reddish-orange mineral of which only a single, tiny sample exists – an 0.3-gram gem – making it the rarest mineral in the world, by far.
There are around 6,000 minerals recognized by the International Mineralogical Association, and while many of them are classified as ‘rare’, none of them rival kyawthuite in terms of rarity. Named after Dr. Kyaw Thu, a Burmese mineralogist-petrologist-gemologist, this incredibly rare mineral was discovered in the bed of a stream in Myanmar’s Mogok region by sapphire hunters and recognized by the International Mineralogical Society in 2015. The only sample ever discovered weighs just 1.61 carats (0.3 grams) and is in the custody of the Natural History Museum of Los Angeles.
Photo: Natural History Museum of Los Angeles.
The chemical formula of kyawthuite is Bi3+Sb5+O4, with traces of tantalum. Interestingly, because bismuth is such a heavy element the density of kyawthuite is more than eight times that of water, making it particularly heavy for its tiny size.
The discovery of the world’s rarest mineral was somewhat of a stroke of luck. The ruby hunters that found it didn’t realize what a treasure they had gotten their hands on, so they put it up for sale at the market. But Dr. Kyaw Thu, who regularly visited Mogok township, aka Myanmar’s Ruby Land, noticed that there was something special about the tiny gem.
“From studying in the field and frequently buying stones from the Khanae market, I could tell that this stone was a little strange and I bought it,” Dr. Kyaw Thu told The Myanmar Times. “Then, when I reached Yangon, I examined it and determined that this was not like any other gem we’ve ever found.”
Dr. Kyaw Thu bought the world’s only known kyawthuite gem in 2010 and worked closely with experts from the United States and the International Mineralogical Association to have it recognized as a new mineral.
You’re probably wondering what this tiny, one-of-a-kind gem costs, but that is pretty much impossible to answer since the only piece of kyawthuite in the world isn’t for sale.