The government said it has imposed the ban on all diamond exports, including those from Rio Tinto unit, until gemstones from its controversial Marange fields are certified by industry regulators.
The government accused Western countries of using the Kimberley Process Certification Scheme, which regulates the global diamond trade, to ban Zimbabwe from benefiting from diamonds.
The ban affected Rio Tinto's Murowa mine, which produced 124,000 carats last year, and privately owned River Ranch, both of which are certified by the Kimberley Process.
Zimbabwe has been waiting for the certification of its Marange diamonds, and on Thursday the Kimberley Process monitor, Abbey Chikane, said he would recommend Zimbabwe be allowed to export the precious stones.
The ban will affect a mine run by Rio Tinto, the Anglo-Australian mining house, and the small, privately-owned River Ranch mine, both of which have Kimberley Process approval to export their rough diamonds.
Human rights groups have charged that political cronies of President Robert Mugabe and the army have mainly profited from illegal mining in Marange.
Human Rights Watch and other groups have been lobbying for Zimbabwe to be suspended from the Kimberly Process and say Marange stones are blood diamonds of a sort, though Harare has responded that diamonds from the district have not funded armed conflict in the region.