An uncirculated coin is simply a coin that has not entered circulation and more likely to be in better shape than a normal coin.Purchasing an uncirculated coin in any type of packaging, such as acrylic coin holders, is more desirable, because you will be more certain of the coin standard.
What makes uncirculated coins more valuable?
The value of uncirculated coins is with the finish of the coin. Uncirculated coins are much less likely to be damaged or have surface wear compared to those in circulation, which means collectors are willing to pay a premium price.
Due to the amount of time taken for them to be securely deposited, historical coins are much rarer to come across in uncirculated form, so it might be worth searching your collection to see whether you happen to own such a coin.
It’s also worth noting that many collectable sets have been released throughout the years and these are typically packaged and sealed correctly to allow them to maintain good quality.
Brilliant uncirculated vs uncirculated
So, we’ve established what uncirculated means, but what about brilliant uncirculated?
Brilliant uncirculated (or BU, B.U, B.UNC) is a term used to describe coins that are of a higher standard than circulating coins. These coins are machine fed into dies that are polished and finished by hand and then struck twice. BU coins are typically produced in base metal but there are some that are issued in gold and silver.
You may be even more confused when you come across the term ‘proof’ for a description of a coin.
A proof coin is similar to an uncirculated coin, but by using a hand-finished die and being hand fed into the press, it finishes to a much higher quality. To ensure the finer features of the pattern are captured, the coins are then hit up to six times under lower pressure.
A piedfort coin is simply a special type of proof coin that is double the weight of the standard proof version of the coin. These coins are usually struck in silver and sometimes gold and are more expensive.
Bullion coins are completely different from the other types of coin mentioned in this list, as they are purely an investment item.
Bullion coins are valued solely for the quantity of precious metal they carry and are only struck with platinum, gold and silver. There is little importance to the standard of these coins, but it is usually similar to a brilliant uncirculated coin.
Reference: The Coin Expert