The sale of the Wrekin Ruby, the cricket ball-sized gem owned by collapsed Shropshire firm Wrekin Construction, has attracted interest from would-be buyers across the globe, it was revealed today.

The ruby, also known as the Gem of Tanzania, has been put up for sale by Wrekin administrators in a bid to claw back some of the millions still owed to creditors. The Shifnal firm went into administration in March.

The company’s collapse led to the loss of more than 500 jobs. The gemstone was listed among the firm’s assets, after it was sold to Wrekin in exchange for around £11 million worth of shares in the company.

Administrators Ernst & Young is selling the ruby through the auction house, GVA Grimley.

However, the sale of the ruby will be completed by private treaty rather than by public auction.

Russell Hobson, of GVA Grimley, said there had been a “good response” to the sale which has a closing date of December 16 for interested bidders.

“People are submitting their best offers at this stage. On December 16, the top 10 bidders will be offered to inspect the ruby and after that they will go and consider their offers.

“Some may decide to pull out, some may consider to up their offer but proof of funding is required at the time of the initial offer.”

GVA Grimley refused to comment on the current number of bidders interested in the gemstone. But it is believed that scores of possible bids could have already been received ahead of the deadline and that a sale could be agreed before the end of the year.

In the sale details, the gemstone is described as “loose hexagonal crystal rough with co-existent green/black crystal matrix on its sides, opaque reddish purple in colour”.

Wrekin owes more than £40 million to more than 1,000 creditors, including a £20 million claim from the company’s pension fund.

The gem was sold to Wrekin by the Tamar Group, run by businessman David Unwin, who also became the chairman of Wrekin Construction when he bought the company in 2007.

It was previously listed in the Tamar accounts as having a value of £300,000 before being sold to Wrekin in exchange for the £11 million of shares.