There are some stamps in the world that are so rare they are priceless, but what makes a stamp rare in the first place?

Tyrian Plum

At the beginning of King Edward VII’s reign his stamps used the same stamp frames as his mother, Queen Victoria. A ‘stamp frame’ is the design you see around the monarch’s head. Some of these early stamps were printed in two colours which was a more expensive process to produce.

Two colour stamps used by Queen Victoria and King Edward VII

Two colour stamps used by Queen Victoria and King Edward VII

Later when the decision was made to produce all the stamps in single colours the printers, De La Rue, felt the design would not be suitable and a new stamp frame was required. Three designs were produced and the Postmaster General preferred ‘No.3’ (shown below). This would go on to become the issued stamp.

New twopenny stamp design, No.3, Aug 1909, KEVII/01/25
Tyrian Plum metal printing die, OB1998.1196
Colour trials of the new twopenny design, 1 April 1910, KEVII/01(L)/16

This design was trialled using different colours and a shade of purple was selected, which became commonly known as ‘Tyrian Plum’.

The stamps were printed in their thousands and sent to the Inland Revenue ready for distribution to post offices. However, it was decided to run down the old stock of two colour 2d (twopenny) stamps before using the new single colour design.

Sheet of King Edward VII 2d stamps, ‘Tyrian Plum’, 11 Apr 1910, KEVII/D/0036
Close-up of the individual ‘Tyrian Plum’ stamp

While the original stock of 2d stamps was being used up, the King died, on 6 May 1910. The Postmaster General decided that the newly printed, single colour, sheets should be destroyed. The only two sheets to survive this destruction are now in the museum’s collection.

Some individual stamps escaped and are on the open market but with so few stamps available, individual stamps are extremely expensive and the two remaining sheets are priceless.

Twopenny Blue

The Penny Black, the world’s first postage stamp, covered the cost of letters up to half an ounce (just over 14 grams) in weight. For letters between that weight and 1 ounce the cost was twopence.

A two penny stamp was produced, called the Twopenny Blue, which was in use from 6 May 1840 along with the penny Black. The Twopenny Blue stamp is extremely similar to the Penny Black except ‘TWO PENCE’ appears at the bottom instead of ‘ONE PENNY’.

Block of the first type of Twopenny Blue Stamps, Phillips Collection Volume VII Page 5
Twopenny Blue Metal Die, OB 1998.0395
Twopenny Blue Registration Sheet, Plate 3, 25 Feb 1841, QV/VR/02/06

Stamps were first cancelled (marked as used) with red ink. However, this could be easily removed, and the stamp reused. A black mark worked better but could not be seen on the Penny Black stamp. Alternative colours were tested and within a year the one penny stamp changed colour to red.

A new blue ink was also prepared for the Twopenny blue stamp that helped prevent reuse. To distinguish this type from the original, a white line was added above and below the portrait of Queen Victoria.

Unlike the Penny Black, Twopenny Blue stamps are a rarer find as sending items through the post at the greater weight was infrequent. Examples of the first version of the stamp are most sought after but full sheets of these stamps no longer exist.

The first sheet (printing plate number 3), with the new additional white lines, is a unique piece currently on display in our temporary exhibition, The King’s Stamp.

Inverted Jenny

The US Post Office issued a new airmail stamp on 13 May 1918 to mark the first official airmail flight, scheduled to take place two days after. The 24 cent stamp featured an image of a “Curtiss Jenny” biplane surrounded by a red frame.

Unfortunately, during the printing process something went wrong. Either the sheet which was already printed with the red frame was fed into the printing press upside down or the printing plate of the plane was the wrong way round. Either way, a unique and unexpected design was produced, featuring the plane flying upside down. Only one sheet of misprinted stamps was sold making each stamp extremely rare and valuable.

24 cent Inverted Jenny Stamp, 1918, image courtesy of the National Postal Museum, Washington

William T. Robey was the lucky collector to buy the sheet and since then it has been broken up and sold separately. The National Postal Museum in Washington holds some of these rare examples.

British Guiana One Cent Magenta

From 1852, the stamps used in British Guiana were produced by UK printers. The postmasters at this former British colony were required to request new stamps in advance of running out to give enough time for them to be printed and posted from the UK.

In 1856 this wasn’t done in time and stamps were printed internally. Though difficult to see, the stamp features a ship in the middle along with the value and the name of the country around the outside.

British Guiana One Cent Magenta Stamp, 1856, image courtesy of Stanley Gibbons

The internally printed stamp was first discovered by the young local stamp collector L. Vernon Vaughan amongst family papers in 1873. Apparently he thought he could find a better example so sold it to a local collector, however no other stamp of this type has ever been found.  The stamp has been sold on many times, ever increasing in value.

The stamp was last sold at Sotherby’s in New York for $8.3 million. The auction winner was the stamp dealer Stanley Gibbons.

Stanley Gibbons are currently widening the ownership of the stamp with anyone being able to buy a share of ‘The World’s Rarest Stamp’.

Rare stamps are produced because of errors, scarcity and simply because the stamp wasn’t used that much. These stamps are often unobtainable to collectors so where possible it is important to make these unique items accessible.

The Tyrian Plum and Twopenny Blue stamps can be seen in our current exhibition The King’s Stamp, which will run until September 2023.



Smithsonian Website Inverted Jenny | National Postal Museum (

Stanley Gibbons Website The ONE CENT Magenta :: Stanley Gibbons

Great Britain: Queen Victoria Volume 1, by Stanley Gibbons Ltd

Just Large Enough by Douglas Muir (available on in our shop)