State-owned Angop news agency quoted the interior ministry as saying that the security personnel also confiscated $49,751 in cash, several rudimentary tools and diamond weighing scales.
The ministry said the diamonds were handed over to the commission overseeing the Transparency Operation.
It pledged to continue fighting against the illegal mining of diamonds in the country.
Operation transparency was launched in December 2018 to combat illegal diamond mining, illegal immigration, and administrative infractions, among other things.
Angola had more than 700 small diamond prospectors before the operation.
Only 260 of them were said to have met the requirements to continue prospecting.
Mathew Nyaungwa, Editor in Chief of the African Bureau, Rough&Polished