China county makes diamonds 'as cheap as cabbage' through industrial-scale production

Zhecheng, a county in China that once specialized in agriculture and livestock, has become a leading producer of lab-grown diamonds and other superhard materials. In 2023, this county contributed to over 70% of the global production of synthetic diamonds, with a significant share of 60% by the next year, according to China Daily. These lab-grown diamonds have driven down prices, earning them the informal nickname "as cheap as cabbage."

Lab-grown diamonds now cost much less than their natural counterparts, sometimes even tens of times less. One-carat lab-grown diamonds are typically priced between 1,000 to 2,000 yuan (US$140-280) online, although prices fluctuate based on quality and other factors. Despite their lower cost, lab-grown diamonds possess the same chemical composition and physical properties as natural diamonds, as they are created under controlled conditions rather than formed deep within the Earth's crust.

The process of creating these diamonds involves subjecting graphite to extreme pressure and temperature, a procedure that can last from seven to 15 days, significantly shorter than the billions of years required for natural diamonds to form. This accelerated production technique has its roots in Henan's early development of synthetic diamonds and superhard materials.

China manufactured its first synthetic diamond in 1963, and Henan later introduced a six-sided press that accelerated production, establishing the groundwork for the region's superhard-materials industry.

The journey of Zhecheng's diamond industry began in the early 1980s when engineer Feng Jinchang returned home to establish the Shaoyuan Diamond Factory, which played a crucial role in nurturing the county's diamond sector. Subsequent decades saw the development of an industrial cluster that linked upstream suppliers with downstream manufacturers, creating a comprehensive supply chain.

Today, Zhecheng extends its reach beyond jewelry to include industrial applications, such as using single-crystal diamond synthesises and micropowders for cutting, polishing, and various other technologies like semiconductors. In 2025, Henan Liliang Diamond Co., Ltd, located in Zhecheng, unveiled a 156.47-carat lab-grown rough diamond at the 15th China Henan International Investment and Trade Fair, which was certified by the International Gemological Institute and recognized as the world's largest known lab-grown rough single crystal.