The Modern Approach to Minting Coins and How It Affects Collectability
Minting coins has come a long way from the days when hand-engraved dies were used to hammer designs into single blanks or molten metal was poured into coin molds. Modern manufacturing techniques and materials have resulted in coining dies that are more precise and durable, giving todays coins a much higher level of quality and consistency.
Making a Modern Coin
One a coin’s design is approved—by the Treasury Department in the case of the United States—an artist creates a wax replica several times the size of the actual coin. This allows for more detail and precision than working at actual size. A plaster of Paris “negative” is made from the replica and carefully refined before being used to make a plaster positive for inspection and approval.
Then a thin copper shell known as a galvano is electroplated over the plaster mold. The galvano is carefully inspected and any defects are corrected before it’s reinforced with lead and mounted on reducing lathe that engraves the coin design into steel blank at actual size to produce a replica called a hub. The hub is then heat treated to harden it and placed in a hydraulic press to prepare a master die that’s used to make the working dies that will be used to make the actual coins at the various mint locations.
Multiple working dies are made for both the obverse (heads) and reverse (tails) of the coins and sent to the mints for coin production. If the coin has an edge design such as reeding or inscriptions, that design will be incorporated into the dies so it will be transferred as the coin blank (planchet) is struck and expands under pressure.
Three Strikes - and Some Foul Balls
U.S. coins are struck at the mints in three different ways: a proof strike, a mint strike, and a circulation or “business” strike.
- Proof Strikes
Proof strikes are the highest quality strikes and are made for collecting rather than circulation. The planchets are carefully handled to minimize abrasions before striking and the coins get a minimum of two strikes to ensure the highest quality. The flat areas, known as the fields, are polished to a mirror finish before striking and the raised areas, called the devices, get a laser engraved frosting. The struck coins are carefully removed from the press by hand and packaged individually. The luster of the field and degree of frosting remaining on a proof coin are major determinants of its value to collectors, along with its rarity. - Mint Strikes
Sometimes the demand for coins or a shortage of metal causes the mint to forgo the time and effort required for proof coin production. This happened most notably in 1965-67 when the price of silver increased rapidly, creating a serious coin shortage.
To keep collectors from too much disappointment, special “mint strikes” are sometimes made. While the elaborate steps taken to make proof coins are skipped, extra care is taken in handling the blanks and finished coins, and the dies are carefully prepared. The coins are packaged specially and sold to dealers to pass on to collectors as stand-ins for proof coins.
While not usually as valuable as proof coins, mint strikes generally are worth more than regular production strikes. - Business (Circulation) Strikes
The business of the Mint is making coins for everyday use, and they do it in the billions. Since the coins are produced at a rate of 120 per minute, the dies are subject to wear and tear and are frequently replaced before the coin quality deteriorates noticeably.
Business strike coins are then bagged to go to Federal Reserve banks to be placed in circulation. The degree of wear or damage is a prime determinant of a coin’s collectible value, ranging from Uncirculated to Poor over the range of the Sheldon Coin Grading Scale. - Foul Balls
When billions of coins are made every year, mistakes are bound to happen. These range from accidental misstrikes to flaws in the dies or even deliberate changes to dates or lettering that result in less-than-perfect coins.
There is a whole category of collectors that specialize in these flawed coins, and their values can range from a few extra dollars to many hundreds of thousands.
Knowing the details of how coins are made is important information to have for collectors. It can keep them from making buying mistakes as well as alert them to valuable coins they might find in circulation or for sale.
Plus, it’s part of the fascinating knowledge that comes with being a coin collector.
