The hoard could be split up and sold privately if the target is not reached
The campaign to keep the Staffordshire Hoard in the West Midlands has received a £50,000 donation from a mystery benefactor.
Fundraisers have to raise £3.3m by 17 April, or the collection may be split up and sold to private collectors.
Since the campaign was launched in January, £750,000 has been raised - £500,000 of which was from Birmingham and Stoke-on-Trent city councils.
The 1,500 gold Anglo-Saxon artefacts were found in a field, near Lichfield.
Over the weekend about 3,700 visitors viewed an exhibition of the Staffordshire Hoard in Stoke-on-Trent.
Hazel Lyth of Stoke-on-Trent City Council said: "This is the first time the hoard has been exhibited in Staffordshire, but it could also be the last if we don't raise enough money."
If the appeal is successful, the hoard would be jointly acquired by both the Birmingham Museum and the Potteries Museum and Art Gallery in Stoke-on-Trent.