Thousands of children work illegally in diamond mines in Congo’s diamond-rich Kasai region – mainly to pay for food and school fees – and girls who live around the mines are prey to rape, forced marriage and prostitution, according to Swedwatch.

Yet few jewellery firms have policies to assess the risk of child labour and abuses in their diamond supply chains, and many do not provide public information about efforts to operate responsibly, Swedwatch said in a report.

Swedwatch also said the Kimberley Process Certification Scheme (KPCS), an initiative seeking to end trade in “blood diamonds” used to finance conflict, was obscuring rights abuses.

The KPCS classifies less than 0.1 percent of the world’s diamonds as untradeable for ethical reasons.

Yet this figure only includes diamonds used by rebel groups to finance conflict, and does not account for diamond extraction involving rights violations across Africa, Swedwatch said.

“The KPCS is outdated and does not cover most human rights abuses linked to diamond extraction today,” Therese Sjöström, a researcher at Swedwatch, told the Thomson Reuters Foundation from Stockholm.

Andrey Polyakov, head of the World Diamond Council (WDC), said the success of the KPCS was based on its focus on conflict.

“However, as WDC, we are against any form of human rights violations,” he said. “As the industry voice, we take it as our responsibility to continue the ongoing discussions within the KPCS to press to reform and further strengthen the process.”

Many of the children who spoke to Swedwatch said they worked in the mines to pay for food or to cover unofficial school fees in a country where education is nominally free. Others were orphans, or abandoned by their parents, and worked to survive.

Sexual abuse and rape of girls and women around the mines is widespread, yet there is no access to professional support for victims, according to Swedwatch, which monitors the impact of Swedish companies on the environment and human rights.

Swedwatch called on the Congolese government to protect children in artisanal mines from illegal child labour, and said jewellery companies should improve the regulation of their supply chains, and work together to demand reform of the KPCS.

The KPCS is chaired by participating countries on rotation. Australia takes over from the United Arab Emirates next year, and will be followed by the European Union in 2018.