How rare is the new Stephen Hawking 50p, and how can you get one?

Earlier this week, the Royal Mint released a new 50p coin in honour of the life and work of professor Stephen Hawking, who passed away a year ago.

The coin's eye-catching design features Professor Hawking's name and his mathematical formula for black-hole thermodynamics seemingly caught in a black-hole vortex.

This rare coin is one of several released by The Royal Mint to commemorate top scientists. The Charles Darwin 50p was released in 2009, while the Sir Isaac Newton 50p coin was launched in 2017, as well as a 2018 design that you could strike for yourself during a visit to the Royal Mint.

Which? explains how rare this new 50p coin is, and how you can get one for your collection.

How can you get a Stephen Hawking 50p?

The coin is not currently being released into circulation, but you can order one on the Royal Mint website. Other coin collecting sites have also advertised it, but you should always check a site's credentials before handing over any money.

The collection of coins include:

• a gold proof coin in a presentation box - only 400 exist, and are being sold for £795
• a silver proof piedfort coin, of which there are only 2,500, costing £95. Piedforts arespecially issued coinswhich are thicker and heavier than the usual specifications
• a silver proof coin, which is one of 5,500, costing £55
• and an uncirculated metal coin, costing £10.

No mintage limit has been set for the uncirculated metal coin.

Despite only being released a couple of days ago, all of the limited-edition coins have sold out, and the uncirculated coins are out of stock.

The coins are already being offered for sale on eBay.

One of the silver proof piedfort coins sold yesterday for £155 - a 63% mark-up on its retail price - after attracting five bids.

That said, be wary of eBay listings at inflated or unrealistic prices, as well as fake listings. Unscrupulous sellers may place their own bids, or fake a sale at an exorbitant price, to make a coin seem more in demand than it is.

• Find out more:the 50p coin celebrates 50 years

Who was professor Stephen Hawking?

Acclaimed physicist professor Stephen Hawking was famous for his work on making difficult subjects more accessible to the public. Inhis seminal book A Brief History of Time, he looked at the Big Bang theory, black holes and whether there was a beginning to time, themes that have inspired the new coin design.

At the age of 22, Hawking was given just a few years to live after being diagnosed with a rare form of motor neurone disease - he ultimately lived until the age of 76. His early life was captured in the film The Theory of Everything released in 2015, for which Eddie Redmayne, in the role of Stephen Hawking, won the Oscar for best actor.

Find out more:the rarest and most valuable 50p, 10p and £2 coins

Which is the rarest 50p coin?

The Stephen Hawking 50p is not currently being released into general circulation, but there's always a possibility of finding a rare coin in your change.

Coin mintages show the number of coins of each design that have been released into circulation.

Broadly speaking, the rarer a coin is, the more valuable it will be. This is true of the Kew Gardens 50p - which has by far the lowest mintage of any other rare 50p coins - and which has made headlines for the high prices people are willing to pay for it.

The 50p coins with the lowest mintages are shown in the graph below.

But there are other factors that can have an effect on a coin's value.

Is it new?

New coins tend to garner a lot of media interest, and therefore become sought after among coin collectors.

Is it part of a collection?

Coins such as the London 2012 Olympic series and the Beatrix Potter collection tend to hold their value and popularity as collectors vie to complete their set.

Plus, as more people find or buy the coins and keep them for their own collection, the amount in circulation is brought down, making them even rarer.

What condition is it in?

When coins are released into circulation, they inevitably get scratched and dirty, giving them a dull appearance. If a coin is uncirculated, or looks as good as new, it's likely to fetch a higher price.

However, bear in mind that a coin's value is only worth whatever someone is willing to pay for it - if you're planning on selling a rare coin, you may only get its face value.