In 2019 to celebrate the Life of Stephen Hawking, the Royal Mint released a special Limited Issue Stephen Hawking Piedfort 50p Fifty Pence Silver Proof Coin struck in solid .925 Sterling Silver.
The reverse designed by Edwina Ellis features a Black Hole to celebrate Stephen Hawking's groundbreaking work while the obverse features the Fifth Portrait of Her Majesty Queen Elizabeth II by Jody Clark.
Piedforts are coins which have been especially struck on thicker than normal blanks.
As their name suggests they are closely associated with France, where from the twelfth century they were apparently issued by the Kings as presentation pieces.
In Britain, the practice of striking piedforts is later and less frequent, but medieval and Tudor examples are known.
These legal tender coins have been struck to proof quality using specially prepared dies and highly polished blanks.
Royal Mint Product Code - UK19STPF