The Coleridge Collar is a gold necklace whose provenance is disputed. It is said to be either a 16th-century chain of office, given by King Henry VIII to his adviser Sir Edward Montagu, on the latter's appointment as Lord Chief Justice of the Common Pleas in 1546; or a 17th-century copy.
A former owner, Lord Coleridge, fifth Baron of Ottery St Mary, was advised by Sotheby's that the collar was a 22-carat copy, and so sold it privately, in 2006, for £35,000.
However, on 6 November 2008 the purchaser resold it, as a 20-carat original, for more than £300,000, via Sotheby's rival Christie's.
Lord Coleridge is now (as of February 2012) suing Sotheby's, at the High Court, London, for the difference. Lord Coleridge lost the case and had to pay some 90% of the costs, about £1 million. <http://www.arthistorynews.com/articles/1173_More_on_the_Coleridge_collar>