The diamonds from the eastern Chiadzwa region, where the army has been accused of human rights abuses, have been accumulating since the Kimberley Process last year ordered Zimbabwe to suspend its diamond exports.
The Kimberley Process (KP) is an international body set up to root out trade in "blood diamonds" - diamonds that bankroll conflict.
In recent weeks, the KP lifted the ban after being allowed to monitor operations at Chiadzwa.
A team from the Kimberley Process led by South Africa's
Abbey Chikane visited the area again on Monday and Tuesday before the
sale
to confirm whether abuses had halted. The team had been expected to issue a
report by Wednesday, but had yet to do so.
Chiadzwa is regarded as the richest diamond find of the century.
"The auction has raised great interest from the world over.
We have buyers from Europe, America and Asia that confirmed
their
participation," Obert Mpofu, Zimbabwe's mines minister told
the German Press Agency dpa.
Mpofu estimated the sale at Harare International Airport could bring in up to $1.7bn, which would equate to over half Zimbabwe's annual budget.
The KP clamped down on Zimbabwe after a brutal crackdown by
the army in 2008 against tens of thousands illegal diamond diggers,
in
which dozens of people were reportedly killed.
- Sapa