The Mandalay Ruby
This 48.019-carat cushion-shaped ruby was offered for sale by Sotheby’s New York on October 18th, 1988 but received no bids. Sotheby’s implied that it may have been the 47-carat J.N. Forster Ruby, which was found sometime before 1877, but this is quickly ruled out. Two large Burma rubies brought to England in 1875, weighing 37 and 47 carats. These were put on the market by the Burmese royal family and were later recut by Forster to 32 5/16 and 39 9/16 ct (or 38 9/16 ct); one sold for £10,000, the other for £20,000, respectively.
Sotheby's also implied at the same time that it could be one other famous yet unnamed ruby weighing 46¾ carats; oblong in form (probably cut); mounted in a brooch with four brilliant-cut diamonds and sold (or bought in) at Christie's of London on May 7th, 1896 for £8000. Many doubt this version of its history as well.
Origin known or not, the Mandalay Ruby is one of the largest fine rubies in the world.