Barrick confirmed chairman John Thornton met President John Magufuli for talks Wednesday, but didn't mention the details of what, if anything, had been agreed.
Gemfields, which mines for emeralds and amethysts in Zambia and for rubies in Mozambique, had already received a buyout offer from largest shareholder Pallinghurst Resources.
The growing market for electric vehicles will significantly impact demand for copper over the next decade, according to new research commissioned by the International Copper Association.
Stuart Chambers, 61 and former chairman of UK chip designer Arm, will join Anglo as a non-executive director in September, replacing Parker in November.