Members of the Kimberley Process group, which certifies diamonds as conflict-free, remain divided on a push to expand its definition to exclude gems funding aggression by states.
KP met in Botswana this week, with the US, the EU, Australia, the UK, Japan, Canada, Switzerland and civil society groups supporting a Ukrainian push to discuss Russia's profits from diamond mining contributing to its invasion of Ukraine.
Russia — which invaded Ukraine four months ago — holds a 33 per cent stake in Alrosa, which accounted for about 30 per cent of the world's diamond output last year.
US sanctions on the company have already affected the industry, and large jewellery retailers have begun suspending sales of Russian diamonds.
“When you see Bucha, Irpin, Gostomel, all those atrocities I think they should think twice when they are buying diamonds that can be of origin of Russia, because they are basically sponsoring the killings,” Ukraine's ambassador to South Africa, Botswana and Mozambique, Liubov Abravitova told Reuters.
Ukraine has accused the Russian military of executing residents of Bucha, a town outside the capital Kyiv that Russian troops occupied for several weeks before withdrawing. Images of bodies lying in the streets drew widespread condemnation from the West.
Belarus, China, Central African Republic, Kyrgyzstan, and Mali explicitly backed Russia within the KP, while Angola signalled its support by leading applause after Russian delegates spoke, two sources at the meeting said.
Because it makes decisions by consensus, the rift over Russia risks rendering the KP ineffective.
Civil society and some state participants are calling for the decision-making process to be reformed, and the leading diamond industry group on Friday acknowledged the push for change.
“There seems to be strong support for further reforms, including that of the conflict diamond definition,” World Diamond Council president Edward Asscher said during the closing ceremony of the KP meeting in Kasane, north-eastern Botswana.
Consumers' growing demand for clarity on the origin of diamonds will likely put pressure on the KP to make reforms, Ms Abravitova said.
A three-yearly review of the KP certification scheme is due next year, and reforms will be discussed at the KP's plenary meeting set for November, Jacob Thamage of Botswana, the KP's current chair, said.
But civil society groups criticised the KP for failing to consider the status of Russian diamonds.
“The fact that the KP is unable to even discuss whether it should continue certifying Russian diamonds as conflict-free, reaffirms what we have been denouncing for years: That the world's conflict diamond scheme is no longer fit for purpose,” Michel Yoboue, co-ordinator of the Kimberley Process Civil Society Coalition, said in a speech at the gathering.
Neither Russia's KP envoy nor Alrosa immediately responded to a request for comment from Reuters.
Reuters contributed reporting