Discovery of ‘new’ gemstone turns coal into gold for Iwate company

The Yomiuri Shimbun
A necklace, right, and prayer beads made of “Kuji jet” are seen in Kuji, Iwate Prefecture, in September.

An amber processing company in Kuji, Iwate Prefecture, has successfully commercialized fashion accessories made from a locally unearthed gemstone that miners didn’t even know they had until recently.

Kuji Amber creates jewelry using jet, a type of coal that is a gemstone. Sales started Sept. 1 and the product, named “Kuji jet,” sold out almost immediately.

Jet is extracted at the same time as amber, and in Kuji, miners had been disposing of it as unburnable coal.

However, around 2014, on the advice of an appraiser visiting Kuji Amber, an investigation revealed the coal was the valuable gemstone.

Many have high hopes jet will become the third local underground resource, after amber and dinosaur fossils.

The Yomiuri Shimbun
A lump of jet mined in Kuji, Iwate Prefecture

Jet is fossilized peat, and it is mined from the same 90-million-year-old stratum as the amber found in Kuji. It is also called black amber.

The gemstone is in high demand in Europe and the United States popularity that dates back to when England’s Queen Victoria wore jewelry made from it for a long time after her husband’s death.

The development of jet accessories started in 2016 but proved difficult because Kuji jet cracks easily when mined. Kuji Amber decided to use its amber processing technology to solve the problem. By mixing amber with jet, the company succeeded in making the jet stronger, less impure and more lustrous than jet from overseas.

A total of 170 products, including pendants, earrings, necklaces, bracelets and prayer beads, went on sale Sept. 1 at retailers and on the company’s website and flew off the shelves.

“I was surprised at the popularity of the products,” said Hisao Shinden, president of the company. “We’d like to make it our second-most popular product after amber.”

Kuji Amber plans to produce 20,000 to 30,000 items a year but, for now, supply cannot keep up with demand.