Proof, BU and Bullion…What Does It All Mean?

Gold sovereigns

In the wonderful world of numismatics, you will hear many terms for the gold and silver that you purchase, and some of the terms that you may hear could be PROOF, BRILLIANT UNCIRCULATED or BU, and BULLION. Here is a quick guide to the differences between the three.


The term Proof refers to the highest striking standard of gold available giving the sharpest, most defined image on the coin. The process of striking a proof coin is as follows:

  • The dies used are hand finished to ensure that all imperfections and blemishes are removed
  • The blank is fed into the coin press by hand
  • It is then struck up to a maximum of six times but at a lower pressure and lower speed than other finishes to guarantee that the image is absolutely flawless
  • After the coin has been struck it is checked for imperfections and then the dies are air-cleaned to make sure that no marks or imperfections can affect the striking of the next coin
  • Due to this process no more than 50 proof coins can be struck in an hour and each proof die may only strike a few hundred coins before it has to be reworked and repolished to maintain the highest possible standard of coin

This is why Proof coins can carry a higher premium but tend to be of a lower mintage, and with that comes the benefit of being more desirable to collectors on the secondary market. This is extremely important if buying for long term value or to pass down through family.

Brilliant Uncirculated or BU

The term Brilliant Uncirculated or BU refers to the middle tier of gold quality. Brilliant Uncirculated coins are not minted or struck to as high a standard as a Proof quality coin as they are struck at a faster rate to Proof coins and they are not put into general circulation. They tend to carry higher mintages and therefore are not as desirable on the secondary market as Proof coins, but as such they do not come at as high a premium.


This refers to the lowest quality grade of coin available. Bullion is mass produced at a far higher speed and can be circulated. The long-term value of the metal used, lies primarily in the weight of the bullion and they come at a lower premium. The word actually comes from the Anglo-Norman term for a melting-house where metal was refined, and before this the French word bouillon, which in English means “boiling.”


So, if you are new to coin collecting and are looking for long term value then bear these terms in mind the next time you purchase because they could have a big impact on the long-term benefits of what you buy. If you are wanting something of exquisite detail and intricacy, go for proof, if you want something that still has a good level of detail and intricacy but is of a higher mintage, then go for Brilliant Uncirculated. If detail and intricacy are not important and it just purely comes down to the weight, then go for bullion.