Yet they spent years languishing unnoticed in the home of an elderly Midlands widow up until her death last year – and could easily have been thrown in the bin.
These treasures are now expected to fetch more than £14,000 when they go under the hammer in Lichfield this month.
Relatives and carers who visited Margaret Hood paid little attention to the plastic carrier bag hanging on a wall in the porch, not realising that it contained the stunning sapphire and diamond ring which is set to form the centrepiece of the auction on March 27.
Margaret, or Peggy as she was usually known, died in October last year, a month after celebrating her 90th birthday.
Suffering from dementia in her later years, she was a confirmed hoarder, and somewhat secretive by nature. So relatives were amazed to discover a spectacular cache of valuable jewellery at her home in Littleover, Derbyshire.
The ring left hanging in a Sainsbury's bag sports an unheated certified 4.16ct Burmese sapphire, estimated to sell at £5,000 to £7,000 when it goes under the hammer with Richard Winterton Auctioneers at The Lichfield Auction Centre.
The preceding lot in the same auction is a pair of early 20th century sapphire and diamond earrings, also estimated at £5,000 to £7,000 and featuring unheated certified sapphires totalling 5.60ct – one Burmese, the other from Ceylon, now Sri Lanka.
The jewels tick all the crucial boxes of origin, no heat treatment and antique pedigree and are causing a stir amongst gemmologists and jewellery collectors.
They are just two examples of the treasures tucked away by Peggy, who had two great grandchildren.
Daughter Sue Bird and son Jonathan Hood said Peggy’s tendency to collect things and her somewhat secretive nature meant that sorting her house after she died proved to be a real treasure hunt.
Mrs Bird, a former exam-paper co-ordinator at Derby University, said: “We didn’t know mum had got all this jewellery – she never told us and it was only by chance we found it all.
“We knew she had inherited some jewellery some decades previously from an old family friend but we had no idea as to the extent.
“She never showed me or my brother and we were gobsmacked when we started to discover all these boxes.
“Mum was a lovely lady but she was the biggest hoarder, she didn’t throw anything away and as the dementia set in she started hiding things around the house.
“She used to save everything, even every plastic bag – after she died we found 316 plastic bags containing greetings cards."
Mrs Bird, 66, said when she and her brother became aware of the extent of what they found, they started going through the belongings with a fine-tooth comb.
“The sapphire ring was in an orange Sainsbury’s bag wrapped up in a big green rambling sock inside another bag and then wrapped in five pop socks," she said.
“It was hanging on the wall by the door and we'd all been coming and going, completely oblivious that this stunning ring was hidden in plain sight.
“It was after discovering the ring we had to say ‘right, do not throw anything away’.”
Mrs Bird said she knew her mother had a safe, but had no idea where the key was, eventually finding it in a CD rack behind 300 CDs.
“When we finally opened the safe we found lots more treasures including the sapphire earrings as well as the empty box for the sapphire ring,” she said.
Mrs Bird said researching the stones provided her with something positive to focus on as she dealt with the grief of losing her mother.
It was a doubly emotional experience, as her father John had died three years before, also suffering from Alzheimer’s, and her mother had kept all his possessions too.
She said she almost threw away a set of beads, but a jewellery expert at Richard Winterton told her they were butterscotch amber sold at an earlier auction for £420.
Other finds from the safe included an Alabaster and Wilson sapphire and diamond brooch – sold at auction with Richard Winterton for £1,200 – and a gold and enamel sweetheart ring reading ‘Hope’ which made £900.
“To think all of these treasures have been hidden away for years and we had absolutely no idea," she said.
“We could easily have thrown some of them away and never been any the wiser. “It’s an amazing story, really.”