The Rarest Mineral on Earth

The Rarest Mineral on Earth. Kyawthuite, found in Myanmar, is the rarest mineral in the world.
Photo: Natural History Museum of Los Angeles County (NHM)

There is only one specimen of the rarest mineral on Earth, and it's from Myanmar.

The rarest mineral on Earth is kyawthuite. Only one crystal, found in the Mogok region of Myanmar, is known to exist. Caltech's mineral database describes it as a small (1.61-karat) deep orange gemstone that the International Mineralogical Association officially recognized in 2015.

Well-known as a synthetic compound. The only approved Bi-Sb oxide mineral. May be a chemical analogue of clinobisvanite, BiVO₄, but the space groups are slightly different. Not analogous to bismutocolumbite or bismutotantalite.

So it was that kyawthuite was born.

“This is the first in the world. It is not found in other countries,” U Kyaw Thu told The Myanmar Times last week.

The precious stone was originally found by gems prospectors in Chaung Gyi village, Mogok township – Myanmar’s famed “Ruby Land” – part of Mandalay Region. Not realising its uniqueness, the finders set the raw stone out for sale at a market, where U Kyaw Thu saw it and discerned something special.

“From studying in the field and buying stones from the Khanae market, [I could tell that] this stone was a little strange and I bought it. Then, when I reached Yangon, I examined it [and determined that] this was not like any other gem we’ve ever found,” U Kyaw Thu said.

Although he purchased the stone in 2010, confirming its rarity was difficult in Myanmar, so he cooperated with experts from the United States and the International Mineralogical Association. In December 2015, the latter recognised it as the first ever discovered in the world, he said.

U Kyaw Thu has largely kept quiet about the mineral named after him, pending confirmation from the International Mineralogical Association.

The stone is currently being exhibited at the Natural History Museum of Los Angeles County in the United States. The museum’s bi-monthly magazine early this year boasted of having added “the world’s rarest gem to its collection”.

The kyawthuite stone is reddish orange in colour and weighs in at 1.61 carat.

Formula: Bi³⁺Sb⁵⁺O₄
System: Monoclinic
Colour: Reddish orange
Hardness: 5½

The above story is based on Materials provided by International Mineralogical Association.