Like many other mints, the Royal Mint issues bullion coins in precious metals, having much higher intrinsic value than their face value. The quarter ounce (1/4 oz) platinum coins are denominated as Twenty-five Pounds (£25).
The coins are legal tender, but are not intended for circulation. They are targeted at bullion investors or collectors who appreciate the special editions as pieces of art. The coins are typically "one-year" types usually issued in parallel with other denominations with the same reverse designs.
This commemorative quarter-ounce platinum £25 coin was issued to celebrate the 70th Birthday of the Prince of Wales and acknowledge the prince’s increased royal duties in recent years in helping the Queen carry out her role as monarch.
The Royal Mint says:
"With a commitment to serving the nation and supporting Her Majesty The Queen in official duties, The Prince of Wales has dedicated his life to helping others. Now in his 70th year, the prince shows no sign of slowing down. Last year alone saw the prince attend a remarkable 546 official occasions, while he also balances patronage to over 400 charitable organisations. This year The Prince of Wales has had important matters close to his heart keeping him busy, including the arrival of grandson HRH Prince Louis of Cambridge and the marriage of Their Royal Highnesses The Duke and Duchess of Sussex."
His new portrait on the reverse of the coin was designer by Robert Elderton, who also designed the commemorative coin for 40th anniversary of Her Majesty The Queen's coronation in 1993. | 
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