Mr Fathers has been a fanatic for decades as a member of the North Otago Rock and Mineral Club, which stages its annual gemstone and jewellery fair in Oamaru's Scottish Hall today and tomorrow.
Mrs Fathers has caught the bug and both are enthusiastic about seeking out new finds.
"It's a fascinating hobby. It turns into a communicable disease," Mr Fathers said.
On a recent trip to the North Island they searched for fossils.
"We knew there were fossils there, but not exactly where to look," Mr Fathers said.
They went to a quarry, but it turned out to be bare.
Driving back, they spotted a recent landslip beside the road.
They spent about three hours fossicking and finding fossils.
"It turned out to be a glory hole. My back and legs hurt, but we kept on gathering fossils," Mrs Fathers said.
On that trip they also swapped some North Otago fossils for North Island fossils, receiving a mudstone with 200 million-year-old monotis fossils - "when dinosaurs started to appear on Earth", Mr Fathers said.
Those fossils, along with others, will be one of the feature exhibitions at the weekend's fair.
There will also be a display of minerals from around the world.
About 20 exhibitors will be at the fair, which has been held for 40 years. Between 60 and 70 members from various clubs throughout the South Island are also expected to attend.
Apart from the displays, there will be crafts and sales tables at the fair, which opens at 9am today and 10am tomorrow.
The North Otago club has about 11 members, but wants more people to catch the bug and join the club to keep it going.
