Manica is bustling with business and the newfound wealth - manifest in the latest Hummer or a high-end Toyota, always with tinted windows - is flaunted along Eduardo Mondlane Avenue, the dusty border town's only significant road.
It is a new frontier energized by diamonds: new restaurants and shops have opened and offer a wide assortment of practically anything - all imported from South Africa.
The region used to be better known for its high levels of poverty and malnutrition. Now diamond dealers, many of them foreign, watch the luxury vehicles parade from freshly whitewashed terraces and hurriedly revamped hotels.
"The diamonds enter Mozambique in an obscure and clandestine way. Nobody in Manica is permitted to [buy or sell] them because we do not have this mineral," Jose Tefula, administrator of Manica district, told IRIN.
The diamonds are believed to come from the vast Chiadzwa diamond fields in the eastern province of Manicaland, about 90km southwest of Zimbabwe's eastern city of Mutare, not far from the border. Traders use "mules", who often ingest the stones, to smuggle the diamonds into Mozambique, Tefula said.
According to Alberto Limeme, head of the border patrol at Machipanda, the main border post between Mozambique and Zimbabwe: "The diamonds cannot cross the border without proper certification but we don't have enough personnel for adequate control."
Stones worth hundreds of thousands of dollars are allegedly being smuggled in every month. In December 2009 authorities seized more than 500g of diamonds from a single smuggler.
A recent joint operation by the Mozambican Migration Services and Border Patrol to stem the flow had not managed to contain the illegal traffic of the precious stones, Limeme admitted.
Limeme said the Zimbabwean authorities had long been aware of the illegal diamond pipeline but "as long as the Zimbabweans do not clamp down on the illegal trafficking, it will be very difficult for us to restrain the entrance of the diamonds".
Hundreds of thousands of artisanal miners had swarmed into the Chiadzwa region and in late 2008, Zimbabwean President Robert Mugabe sent troops to flush them out after repeated attempts by the police to establish control failed.
A June 2009 report by the international watchdog, Human Rights Watch, accused Zimbabwean security forces of killing more than 200 miners in 2008 - an allegation denied by Mugabe's government - and recommended that Zimbabwe be suspended from the Kimberley Process Certification Scheme, which polices the diamond trade.
The fields are now controlled by the military and villagers are allegedly forced by soldiers to dig for stones for the benefit of senior government officials or military commanders.
A 2009 report, Zimbabwe, Diamonds and the Wrong Side of History, by Partnership Africa Canada, one of the architects of the certification scheme, states: "Zimbabwean diamonds are produced from mines that benefit political and military gangsters, and they are smuggled out of the country by the bucket-load."
Risk and reward
One Zimbabwean diamond trader in Manica, who wished to remain anonymous, told IRIN that "people are very willing to risk their lives to carry diamonds across the border".
But there were risks involved: "In Zimbabwe it is necessary to bribe the soldiers guarding the mines and then you still have to make the journey across the mountains to get to the border. But this is creating a lot of wealth in Manica."
Diamonds were sold to foreign buyers by the gram at about 1,350 Meticais (US$46.50), far below average global prices, he said. Dealers from Mali, Nigeria, Somalia, the Great Lakes, Israel and Lebanon then take them out of the country to be processed and sold on the global market.