Rosalind Franklin 50p (2020)

Only brilliant uncirculated and proof versions of the Rosalind Franklin 50p exist, so the price depends on condition and whether the coin is still in its packaging. The original Royal Mint pack commands more than a loose coin or one moved into a capsule or third-party card. Scratches, fingerprints and spotting reduce the price, and so does a pack that has been opened or damaged. Franklin was also struck as a silver proof, a silver piedfort and a gold proof, each with its own price.

The Rosalind Franklin 50p was not issued for circulation, so it has no rarity rank.

The reverse is split in two: a rendering of the X-ray photograph on the left and lines of text on the right, starting with ROSALIND FRANKLIN and then DNA, followed by the title of the photograph. No portrait of Franklin appears, so the word DNA beside the image is the surest sign. The obverse shows Queen Elizabeth II with the date 2020. It was sold in educational packaging telling her story and was not struck for circulation, so it is not a coin you should expect in change.

Rosalind Franklin, the English chemist born in 1920, is best known for her part in the story of DNA, but she was also a leading authority on the structure of viruses, coal and graphite. She died of ovarian cancer aged 37. The Royal Mint marked what would have been her 100th birthday with this 50p, the second coin in its Innovation in Science series after the Stephen Hawking 50p and the first UK coin to celebrate her. It was developed with King's College London, where she carried out her DNA research. Royal Mint graphic designer David Knapton built the reverse around Photograph Fifty-One, the X-ray diffraction image Franklin took that proved essential to modelling the helical structure of DNA. The image sits on the left of the coin, and lines of lettering to its right give her name, the word DNA and the photograph's title, with the initials DK. Queen Elizabeth II appears on the obverse in Jody Clark's fifth portrait.

In the Innovation in Science set it followed the Stephen Hawking 50p of 2019 and came before the John Logie Baird 50p of 2021.