The armed robbery took place at the Guildhall Street store on Saturday, May 14, when two men dressed as police forensic officers made off with £80,000 worth of jewellery.
They threatened shop staff with hammers before taking gold and diamond jewellery and escaping in a green Vauxhall Astra, which was found ablaze in Lindum Terrace minutes later.
Now, James Usher and Son has released information about the stolen items for the first time.
The individual pieces range from engagement rings to necklaces, the most expensive being a ring valued at £14,500.
Store manager Scott Ward said: "The two most expensive pieces we had stolen were hand-made.
"They were in the window the thieves targeted, but we have no photographs.
"They were individual, one-of-a-kind rings.
"The £14,500 ring had a 1.51 princess-cut diamond, with a trilliant-cut diamond on either shoulder.
"The second most expensive piece was a slightly smaller version of this ring, worth £8,850.
"We also lost an 18-carat white gold, two-stone diamond cross over ring, with diamond-set shoulders. The two centre stones weighed in at .55ct each, and the ring was worth £5,225.
"The list of items stolen also includes a platinum-mounted, emerald-cut diamond ring, with a centre stone which weighs .81ct. It has a really fine cut diamond, and is valued at £4,850."
Several other engagement rings were stolen, ranging from £530 to £850 in price, alongside a necklace worth £1,300.
Lincolnshire Police told the Echo there had been no further developments in the case as yet, but added they were hoping the Crimewatch reconstruction, which was filmed on Thursday, May 27, would attract wider attention to the case.
Detective Sergeant Pete Grayson, of Lincoln CID, was on hand to help the BBC team during the reconstruction.
"I'm hoping the reconstruction is going to appeal to a wider audience outside of Lincoln," said DS Grayson.
"If the people who committed the robbery are from outside of the city, then I'm hoping the televised reconstruction will appeal to someone who may know something about the planning or the execution of the crime.
"On top of that, we are still looking at things that have been submitted, which may result in DNA or fingerprint evidence, which could possibly connect an individual to the scene of the crime."
The reconstruction of the James Usher armed robbery will appear on the BBC's Crimewatch Roadshow on June 24, although the date is subject to change.
Anyone with information about the robbery should call police on 0300 111 0300.