The Bronze Age bracelets and Roman jewellery are on loan to the CARAD Rhayader Museum and Gallery.
Peter Cox, chairman of trustees at CARAD, called the exhibition "a real cultural coup for Wales".
The exhibition has received a grant from Cyfoeth Cymru Gyfan (also known as the Sharing Treasures Scheme), a Welsh Government scheme to display treasures from national collections in regional museums.
Accidental finds
In 1899, James Marston wedged a metal bar into a crevice on Gwastedyn Hill as he tried to disturb a fox for his dog to chase. He discovered a Roman ring, bracelet and necklet from the 1st or 2nd Century.
The second gold discovery was made a generation later by 17-year-old labourer John Smith as he helped to plough a field in 1954. What he first thought were old bedsprings turned out to be Bronze Age torcs, or bracelets.
Sheila Jewell, the granddaughter of James Marston, said she was excited that the gold was returning to where it was found. "It was whipped away with undue haste to the British Museum in 1899," she said.
"The family did feel strongly about it being taken to London so quickly, back all those years ago, so it's wonderful to see it back in Rhayader."
Her feelings were echoed by John Smith, who has contributed memories of his find to the exhibition.
"It's nice to know now they're coming back here and everybody can go look at them, take them in and maybe even take an interest in... looking on the ground, as and when they go out, and what's in their gardens."
The exhibition will run until 4 September.
Source: BBC News Website [June 03, 2011]