In coin grading, a “super grade” usually refers to a grade of 67 or above on a scale of 70. The term has gained in popularity over recent years and should be further examined.
To qualify for a super grade, a coin must meet a number of criteria. It must be struck extremely well, with all of the design clearly visible; it must also retain the entirety of its design with no visible wear, particularly on the high points of devices. Surfaces must be very clean, especially on proofs; business strike coins must retain their full original luster. The coin must have excellent overall visual appeal, with little or no discoloration. Some very specific flaws may cause a coin to miss a super grade; expert graders must weigh all of these factors.
Coins are examined by graders on an individual basis, and grades are awarded without regard to the type of coin being graded; savvy collectors must be aware that a super grade may be relatively common for certain types of coins. For example, with significant improvements in modern minting technology, most modern coins emerge from the mint in excellent condition. For example, almost every single modern-day American Silver Eagle emerges from the mint with a grade of 68 or higher. Depending on the year and mint, a significant percentage may even grade 70. So, in the context of modern coins, a grade of 67 or higher is often nothing special.
On the other end of the historical spectrum, early coins are often some of the hardest to find in super grades. This is due to both less-advanced minting technology and the age of the coins. The satellite US Mint facilities set up on the frontier at Charlotte and Dahlonega used particularly primitive equipment; gold coins from these mints are basically non-existent in super grades today.
Low mintages of early coins are also a factor. Often, the availability of super grades is simply a function of a coin’s commonality; it is only logical that there will be more fine examples of coins in existence if the overall mintage is high. Very common silver coins, such as Morgan dollars and Mercury dimes, are some of the easiest vintage coins to find in super grades.
A number of other different factors impact the availability of super grades. Generally speaking, these higher grades are easier to find in smaller coins. In an age when circulation US coinage was often delivered from the Mint in bags, the heavier coins would often suffer significant wear simply from rubbing against each other and the bag itself even before leaving the Mint’s possession. Thus, “bag marks” are quite common on US gold coins. Larger gold coins in particular, such as $20 Double Eagles, are very hard to find in super grades. Smaller coins were usually less susceptible to this sort of damage and are easier to find in these higher grades.
Given how hard it is to achieve a super grade, there is often a huge jump in price for these coins. More advanced collectors may try for a full set of coins with super grades, and collections of super grade coins have recently gained in popularity.