The Mona Lisa of Stamps

Wealth-Bulletin.com reports, "A record for the world's most expensive postage stamp is likely to be set this weekend, when a Swedish stamp, described as 'The Mona Lisa' of the philatelic world, goes on sale with an estimate sale price of around €2m (approximately $2.5 million )."

The 1855 Swedish Treskilling Yellow, shown here, will go under the hammer on May 22 at Feldman Galleries, Geneva, without a reserve price.

David Feldman, founder of the Swiss auction house, is quoted as saying in the piece by Tara Loader Wilkinson, ""As the Mona Lisa is to the art world, and the Hope Diamond is to jewels, so the Treskilling Yellow is to postage stamps."

What makes it so valuable?

According to Amey Stone, who writes on the Luxist website, "Back in Sweden in 1855, when the currency was known as the skilling, the 3 skilling stamp ('treskilling') was printed in green. An 8 skilling stamp was printed in yellow. But due to a printing error, a few 3 skilling stamps were printed in yellow. No one knows how many."

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