Over the weekend, The Treskilling Yellow, a rare Swedish stamp was sold in a quick telephone auction held in Geneva. While the exact sale price is not known, the bidding started in the vicinity of $2.3mm USD, which makes it not only the most expensive stamp but also, the world's most valuable object, by weight.

The 3 Skilling Swedish Stamp, issued in 1857 is precious because of its unusual color, which should been green, but for some reason was yellow. While it is believed that about eight of these were issued, only one has been found.

According to the experts it was used to mail some correspondence and first discovered by a seven-year old schoolboy, who was looking through his grandfather's letters in 1883. He tore it off the envelope and sold it for seven kroners (about one dollar). It is believed that had he not taken it off the envelope, the stamp would have been worth even more.

Since then it has changed hands many times, the last in 1996 when it was sold for $2.3mm USD. Nobody knows who bought it then and the auctioneer is being secretive even this time around, saying very little except,that it is still the most expensive stamp in the world!

sources: onenewspage.com, famousstamps.org, dailymail.co.uk