It must be noted that the term ‘proof’ reflects the process by which coins are struck. It is not an assessment of a coin’s quality. Pre-decimal Proof coins, in particular, are not always found in perfect condition.
The confusing thing for a novice is that Proof coins look, essentially, the same as the coins struck for circulation. They share exactly the same design and are made with the same metals.
So why are they so much more valuable?
First, unlike ordinary coins, Proof coins are not intended for circulation. They are created purely as display models – mini pieces of art to be archived in Government vaults as perfect examples of their circulating cousins.
Also, while ordinary coins are minted by the million in a factory environment, Proof coins are the product of extensive preparation and careful production.
The dies are hardened and brushed so the design is sharp and almost three-dimensional in appearance. They are also struck twice to ensure a sharp, well-defined design.
The blanks are hand picked and highly polished to produce a coin with a mirror shine and smooth fields.
The rims of the struck coins are high, creating a picture-frame effect encasing the design. The pristine nature of the striking is particularly evident in the denticles. They are crisp and uniformly spaced around the coin’s circumference.
Because of the length time involved in their production, proofs are usually struck in restricted numbers. Along with their perfect quality, this is the main reason why they are so valuable.