A piedfort is an unusually thick coin, often exactly twice the normal weight and thickness of other coins of the same diameter and pattern. Piedforts are not normally circulated, and are only struck for presentation purposes by mint officials (such as patterns), or for collectors, dignitaries, and other VIPs.

In the second release in the Innovation in Science series, the Royal Mint marks what would have been Franklin’s 100th birthday with a commemorative 50p coin. Available in limited-edition gold Proof, silver Proof and silver Proof Piedfort, as well as a Brilliant Uncirculated edition, it acknowledges her immense contribution to advancing humanity’s cause.

Rosalind Elsie Franklin (1920–1958) was an English chemist and X-ray crystallographer whose work was central to the understanding of the molecular structures of DNA (deoxyribonucleic acid), RNA (ribonucleic acid), viruses, coal, and graphite. Although her works on coal and viruses were appreciated in her lifetime, her contributions to the discovery of the structure of DNA were largely recognised posthumously.

Franklin is best known for her work on the X-ray diffraction images of DNA, particularly Photo 51, while at King's College London, which led to the discovery of the DNA double helix for which James Watson, Francis Crick and Maurice Wilkins shared the Nobel Prize in Physiology or Medicine in 1962. Watson suggested that Franklin would have ideally been awarded a Nobel Prize in Chemistry, along with Wilkins, but, although there was not yet a rule against posthumous awards, the Nobel Committee generally did not make posthumous nominations. After finishing her work on DNA, Franklin led pioneering work at Birkbeck on the molecular structures of viruses. Her team member Aaron Klug continued her research, winning the Nobel Prize in Chemistry in 1982.

Tragically Rosalind Franklin died of ovarian cancer aged just 37, denying her the awards and recognition that would surely have come during her lifetime.


The fifth crowned portrait of HM Queen Elizabeth II facing right, wearing the George IV State Diadem and drop earrings.

The George IV State Diadem, officially the Diamond Diadem, is a type of crown that was made in 1820 for King George IV. The diadem is worn by queens and queens consort in procession to coronations and State Openings of Parliament. The piece of jewellery has been featured in paintings and on stamps and currency. It can be seen in the Queen's Gallery at Buckingham Palace.

ELIZABETH II DEI GRATIA REGINA FIDEI DEFENSATRIX means Elizabeth II, by the grace of God, Queen and Defender of the Faith.

Engraver: Jody Clark



Inspired by the historical injustice of the failure to credit Franklin’s role in determining the structure of DNA, the graphic designer uses the printing techniques of the era to restore her rightful legacy. By including her name in the design along with Photograph 51, the groundbreaking image she captured with Raymond Gosling of the building blocks of life, he places Franklin at the heart of the DNA story.

Photo 51 is an X-ray diffraction image of a paracristalline gel composed of DNA fiber taken by Raymond Gosling, a graduate student working under the supervision of Rosalind Franklin in May 1952 at King's College London, while working in Sir John Randall's group. The image was tagged "photo 51" because it was the 51st diffraction photograph that Franklin and Gosling had taken. It was critical evidence in identifying the structure of DNA.

Design: David Knapton

Photograph 51


50 Pence

5th portrait, Silver Proof Piedfort Coin
Type Commemorative Issue (Non-circulating)
Material Silver
Fineness 0.925
Weight 16 g
Diameter 27.3 mm
Thickness -
Shape polygon
Sides 7
Alignment Medal
Royal Mint

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