Like many other mints, the Royal Mint issues bullion coins in precious metals, having much higher intrinsic value than their face value. Most of these by tradition are measured in troy ounces of fractions thereof, but the mint also introduced metric coins measuring one kilogram of pure metal (they are actually fractionally heavier as a whole, to account for the small amount of other metal in the alloy).
The 1 kg silver coins are denominated as Five Hundred Pounds (£500), although their intrinsic (bullion) value is much higher than their face value. The coins vary in design depending on the occasion (they are "one-year" types usually issued in parallel with smaller denominations with the same reverse designs).
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 2025 Year of the Snake coins are part of the Royal Mint's Shēngxiào Collection - a coin series dedicated to the Chinese Lunar calendar. The reverse design by US Mint designer Chris Costello has been inspired by the European adder snake.
The mint says:
"The Shēngxiào Collection continues with a coin celebrating the Year of the Snake. Those born under this sign often share the characteristics of strength, intelligence and adaptability."
The range was released on 5 September 2024, in advance of the Chinese Lunar Year of the Snake (29 January 2025 - 16 February 2026). | 
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