Question about graded proof coins in crummy condition

Romankow

I understand that proof coins are specially made (highly polished dies, multiple strikes, etc.). What I don't understand are graded coins (encapsulated from PCGS, NGC, etc.) that are labelled proof, but have numerical grades that are substantially less than 70 (for example, PF60, PF50, or PF30). How do the graders know that those coins are proof coins, and are not just regular strikes with grades of 60, 50, or 30? I understand that some coins were ONLY available as proof coins, so those coins, even if they are in crummy condition, HAVE to be proof, because they weren't ever available as regular strikes. But what about others? How do the graders know that crappy, worn-out coins were once proof strikes?

Here is an example, which was posted to this forum recently:

GaCoinGuy

There are ways to tell; one of the easiest tells is the rims. The fields are also a way to tell.

Coins4Eli

Lets say for example, that you have a proof Morgan dollar. When it was first stuck it had mirror surfaces. Even if it was worn down to lets say a PR 45, it would be evident that the coin is proof, because the coin originally was very well struck. The areas around the devices would also still support the mirror look you expect in proof coinage. Sometimes there are specific diagnostics for proof coins that can also be used if the coin is worn, some die varieties are only struck as proofs. If the coin was worn down any further, it can be nearly impossible to tell, at that point the coin is usually just graded as a business strike.
Edit: Spelling

Manifest_Destiny

I collect seated quarters. Many proof dies have die markers not found on business strike dies.

Insider3

Coin dies are microscopely unique due to the way they are produced. When records of their differences are kept, one can distinguish (along with the usual characteristics of a Proof strike) the circulated Proofs from circulated MS coins. For some series this can be difficult because Proof dies were also used to strike coins for circulation after they were retired.

MFeld

In the case of dates produced in both Proof and circulation strike formats, there are clues to look for, such as strike, sharp rims, the edges and remnants of once-brilliant surfaces (especially in the protected areas). Additionally, some such issues were struck from Proof-only dies, apart from the circulation-strike dies of the same year. However, if a Proof has been circulated and worn beyond a certain point, it might be impossible to determine the method of manufacture.

TrickleCharge

Often the coin can still be tied back to specific dies that were only used for proofs. In some cases though the same dies were used for both proof and business strikes. In a well circulated example with shared dies there may be no way left to identify one from another. In these cases the graders often just assume it is the strike type with the most survivors, be it proof or business.

lilolme

I don't normally know this or TD. But I had a reason to look this up in the past and recalled it here. The 1873 proof has a die scratch on the obverse. Described in coinfacts:

https://www.pcgs.com/coinfacts/coin/1873-t-1-trade/7053

Note: So far as is known, Proofs of the varieties described above under nos. 1 and 2 are all from a common obverse die. There is a fairly deep die scratch extending straight from the bottom left segment of the bale, at an angle slightly upward through the folds of Miss Liberty's gown, terminating in the waves of the sea. Although this prominent feature has been ignored for many years, it was mentioned by Lyman H. Low in the description of an 1873 Proof trade dollar in the R.T. Rose Collection Sale, September 9-10, 1909: "A distinguishing feature of this specimen is a well defined line (in the die) through the outer skirt of Liberty, extending from the cotton bale to water."

The OP coin in this area:

The coinfacts images page for the 1873 proof (not cameo):

https://www.pcgs.com/coinfacts/coin/1873-t-1-trade/images/7053

Romankow

Wow. Thanks for all of this great info everybody. Much appreciated!!

davewesen

sometimes they did not produce MS coins that year. Other times the die type is different between on MS/PR on one side

coinbuf

I sure wish you hadn't used the word crummy in your title, now I'm thinking about cookies.

lcoopie

Take a look at CoinFacts and compare a proof to circulation strikes to see the differences, for example Morgan’s.