There is no doubt that the NGC Ancients grading program has become the standard of the US Ancient coin market. Americans want graded coins. Europeans not so much, at this point. Yet the enormous increase in the ancient coin buying population is clearly coming from US buyers who are moving from US and World coins into Ancients, where relative rarity, beauty, and historical importance clearly still yields tremendous value compared to the US and World markets, in spite of the recent run up in prices.
But, for those not used to Ancients, where no two coins are exactly alike even from the same issue - even from the same dies - understanding grades and assigning value is still often a daunting task.
The beginner often looks first to the Overall Grade. Mint State grades almost always command a premium over lesser grades. But even rank beginners can tell the difference between a Mint State Caesar portrait of awful style and a terrible strike and a beautifully engraved and well struck Caesar portrait:
Choice VF CAESAR PORTRAIT: $17,500
CAN YOU TELL WHY? (I'm sure you can)
It's encouraging that US collectors are making distinctions on elements other than the grade. However, There are a few hard and fast rules that will keep new collectors from making horrible mistakes:
1) THE SURFACE GRADE IS NOT IRRELEVANT. A 1/5 on the surface indicates a coin that has been altered to the point it is NO LONGER FUNCTIONALLY AUTHENTIC. Be careful, even with coins that have been expertly altered so that they look great. This is functionally the same as a forgery. It will never have much resale value. Think of the Mona Lisa. If an expert restores small portions of the background that have been cracked or dirtied with age - well, that's probably fine, it's still the Mona Lisa. But if a vandal spray paints the canvas black, and an expert comes in and repaints the Mona Lisa - well, really, it's not the Mona Lisa anymore- even if it looks great.
A 2/5 will indicate a coin with some problems - perhaps a bit of smoothing in the field. Depending on the issue, while a problem, it is not necessarily devastating. It will affect the value but, depending on the issue, the coin can retain real value. Especially if most coins from the issue exhibit the exact same problem. However, if there is extensive surface damage or problems, the value can certainly suffer.
A 3/5 can be absolutely fine. Usually the problems are scrapes and digs. If these are faint and in the fields they may not detract much from the price at all. A small scratch RIGHT ON THE FACE even if the coins is 4/5 can be a real problem for many collectors, for obvious reasons. On the other hand, an unobtrusive banker's mark in the field might just make the coin more interesting while dropping the grade to 3/5. USE YOUR DISCRETION.
2) The Strike is also vitally important. A 5/5 is obviously great. 4/5 usually indicates some centering issues, if these are minor and all the relevant images and legends are still on the flan, this can be okay. Especially if most coins from an issue display the same problems. But if important design elements are off the flan: the value will certainly be compromised. Know your issues.
3/5 on the strike is very very tough on resale value.
Fine Style: Vitally important for most ancients. Yet, this is very subjective. NGC is as good as anyone at identifying Fine Style. Yet any two experts can still disagree. Sometimes a coin just strikes someone as beautiful and someone else will disagree. Sometimes, though not technically Fine Style, a coin can display a "BOLD" or "Interesting" style - especially with archaic coins - that is just as valuable. Develop your own taste. You should be able to tell what you feel is a fine style. Then you will never be disappointed with a purchase.
FINALLY AN ELEMENT NOT DEALT WITH IN THE GRADING PROCESS THAT CAN GREATLY AFFECT THE VALUE: DIE STATE and METAL QUALITY: a coin struck from fresh dies can greatly enhance the eye appeal, and thus the value. The same goes for a coin struck on beautiful metal. A coin struck from Rusty and/or Worn dies can greatly adversely affect a coin value. Look at the Caesar coin above. The metal quality is atrocious. The die state and metal quality is not accounted for in the grading process. Take this into account.