Hundreds of workers gathered to drive to the main base
Hundreds of former workers at a construction company have staged a protest days after 420 people lost their jobs.
Shropshire-based Wrekin Construction confirmed last week that it had gone into administration.
It has emerged that the company has a ruby, the so-called Gem of Tanzania, listed as an £11m asset.
The workers met at a service station on the M54 in Telford before driving to the headquarters in a convoy.
Several former employees told the BBC they were angry at what had happened to the company.
One likened the firm's acquisition of the stone to something "out of a Disney film".
End of year accounts show that in 2007 the company exchanged £11m worth of shares for the ruby.
Its valuation was apparently confirmed by an Italian institute of gemologists.
The accounts state that: "The fair value of the ruby gemstone was determined by a professional valuer at the Instituti Gemmologico Italiano based in Valenza, Italy, on 31 August 2007."
The convoy of drivers arrived at the site with a noisy fanfare
Administrators Ernst & Young said the company had tax liabilities of more than £3.5m and was due £2m from government contracts at the time of announcing the job cuts last week.
It is also the subject of about 40 county court judgements, the spokesman added.
However, he was unable to comment on whether the stone would be put up for sale.
"There is no confirmation or information on the ruby or its value," he said.
"There is no information on assets at the moment nor will there be in the short term."
Wrekin said it had millions of pounds of orders and blamed Royal Bank of Scotland for its situation, because the bank would not extend credit to cover cash-flow problems.
The redundancies are at bases across Shropshire, Yorkshire, Northamptonshire and Cheshire.
A skeleton staff of 70 has been kept on at the Shropshire headquarters in Shifnal to help administrators wind down the business, a spokesman for the accountants said.