1918 Inverted Jenny is valued at around $3m

Inverted Jenny

Estimated value: US$3 million

The 24-cent Jenny stamp was the first stamp for air-delivery issued in 1918. The stamps were printed on sheets of 100, but each sheet had to be fed through the printing machine twice. Therefore, it was very easy to accidently flip the sheet on the second pass, and this is exactly what happened. One of these sheets was printed with the jenny plane upside down, and sold before the error was noticed. This was how the Inverted Jenny got created.

Only 100 pieces of the Inverted Jenny can be found in the world nowadays. A block of 4 stamps was purchased in 2005, for US$3 million.

1840 UK's Penny Black is the first stamp issued in the world

Penny Black

Estimated value: US$5 million

The UK's 1840 issued Penny Black is the first stamp in the world. It was designed by Rowland Hill, who proposed the reform of the British postal system. He was called the Father of the Postage Stamp.

Before the Penny Black was issued, post offices had to take payments for mail delivery in cash. People had to wait in line to deliver every piece of mail. Postage was charged by the number of letter papers and the amount of distance traveled. Following Rowland Hill's suggestion, a letter was wrapped in an extra piece of paper (envelope) and an adhesive stamp was attached to indicate the prepayment of postage. The stamp was the Penny Black.

The picture in the stamp shows Queen Victoria, based on a sketch of her by William Wyon when she visited London in 1837. The Penny Black Stamp was only used for one year because the red cancellation mark was hard to spot on its black background. As a result of this, nine months later, the stamp was reprinted as a red stamp so that the black cancellation marks were easier to see and harder to remove.

The Penny Black was scheduled to be issued on May 6. However, in some cities, a number of the copies were issued on May 2. Only two pieces of the early issue can be found now and these are regarded as real treasures. A few years ago, a rich businessman bought a copy from a US auction house at the price of US$5 million.

The most rarest stamp in the World

Treskilling Yellow

Estimated value: Much higher than US$3.14 million

The Treskilling Yellow is a Swedish postage stamp, which holds the world's record auction sales price for a single postage stamp.

The normal three-skilling stamp, printed in Sweden, should be green, whereas the eight-skilling stamp was printed in yellow. However, due to an unknown error in 1855, (most likely because the three-skilling plate was accidently replaced by an eight-skilling one), the three-skilling stamp was printed in yellow, creating the precious Treskilling Yellow stamp.

The only known copy in existence of the Treskilling Yellow, was discovered by a schoolboy named Georg Wilhelm Baeckman in 1886, while going through his grandparents' attic.

The stamp made headlines in 1984 when it was sold for 977,500 Swiss francs (US$1.07 million). At a 1990 sale, it made over US$1 million, and then in 1996 it sold again for 2.875 million Swiss francs. Each successive sale meant a world record worth for a postage stamp.

Being one of the most expensive objects in the world, the stamp was auctioned off once again in Geneva, Switzerland, in May 2010. The exact price and the identity of the buyer were not disclosed, but the auctioneer David Feldman released that "it is more expensive than any other single postage stamp in the world."

Post office of Mauritius - Rare Stamps

Post Office Mauritius

Estimated value: US$1.67 million

Post Office Mauritius is an error postal stamp issued in Mauritius.

In September 1847, Lady Gomm, Mauritius' governor's wife, invited friends and celebrities to a ball. For the convenience of sending out the invitations, the Mauritius Post Office issued a set of stamps designed by Joseph Barnard, following the pattern of British stamps. However, the words of "Post Office" instead of "Post Paid" were engraved on the copper plate of the stamp, which produced a big mistake. A total of 240 pieces of this stamp were sold before the error was noticed.

There are only 26 known pieces of the Post Office Mauritius stamps that have survived to this day, including several 14 one-penny and 12 two-penny pieces. In 2011, a blue two-penny Post Office Mauritius was auctioned off for 1.05 million pounds (US$1.67 million) in the UK.

The Whole Country is Red - Rare Stamp

The Whole Country is Red

Estimated value: US$474,197

The stamp that goes by the name of The Whole Country is Red, issued in 1968 during the Cultural Revolution, is a famous stamp with error printing. The stamp features a red map of China imprinted with the golden words "The Whole Country is Red", plus a picture of a worker, a farmer and a soldier holding the "Selected Works of Chairman Mao." The face value of the stamp is 8 fen (1 US cent).

The stamp was only issued for less than half day. An editor of SinoMaps Press found that the map on the stamp was not accurate and reported it to the Ministry of Post and Telecommunications. As a result, all Chinese post offices had to stop selling the stamp and return all the copies. Only a small quantity of the stamp went to private collections.

A large version of the stamp, two times bigger than the original one, was auctioned off for 3.68 million HK dollars (US$474,197) in Hong Kong in 2009, setting a new record for the price of a single stamp auctioned off in China. On the same occasion, 6 normal pieces of the stamp were auctioned off for a total of 2.93 million HK dollars (US$377,482).

Cape of Good Hope stamp - Estimated Value

Issued in 1853, the Cape of Good Hope stamp is the first postage stamp in the Cape of Good Hope, and even in the whole of Africa. It firstly came out in the forms of 1- and 4-pennies, and the stamp with two other face values was issued two years later.

The stamp sports a triangular shape, so that even the illiterate could tell that it was not a stamp from another country, although many other countries have issued triangular stamps since then. Its design is a female figure sitting on top of an anchor, which is resting on top of a rock, symbolizing the Cape. The stamp was designed by Surveyor General Charles Bell and printed by Messrs. Perkins, Bacon & Co., a famous printer of books, bank notes and postage stamps.

Very rare copies of the stamp have survived today. In the world-famous Stanley Gibbons Stamp Catalog, the value of a single Cape of Good Hope stamp is about US$40,000.