An amber processing company in Kuji city of Japan’s Iwate prefecture has successfully commercialised fashion accessories made from a locally unearthed gemstone that local miners didn’t even know they had until recently.

Kuji Amber creates jewellery using jet, a type of coal that is also a gemstone. The company began making accessories out of the mineraloid, with sales starting on September 1. The products, branded as “Kuji jet” sold out almost immediately.

According to the company, Kuji is the only place in Japan that currently mines jet, and in mid-October, it has scheduled a meeting in Japanese capital Tokyo with vendors from across the country to increase sales channels.

Miners in Kuji had been disposing of jet as unburnable coal. The gemstone is fossilised peat, and it is mined from the same 90-million-year-old stratum as the amber found in the city. It is also called black amber.

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

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

The gemstone is in high demand in Europe and the US, partially influenced by England’s Queen Victoria’s penchant for wearing jewellery made from the mineraloid for a long time after her husband’s death.

Kuji Amber began development of jet accessories in 2016, which proved difficult because Kuji jet cracks easily when mined.

The company decided to use its amber processing technology to solve the problem. By mixing amber with jet, the company succeeded in making the mineraloid 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 on September 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 number-two product after amber.”

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

“The high quality of our products is sure to catch the attention of traders,” Shinden said. “In the future, we’d like to expand the possibilities of this type of jet by selling it overseas and setting it on watches and stationery.”