Grading Standards used on this site
The coin community is awash with terms used in the grading of coins and these are the terms used on this site. Starting with the worst;
Clear date; the date is generally the only thing which is clear! Used mainly for bronze coins 1860-1895, which because of their design have the date protected in the exergue (the bit below the design). Coins in this condition will only be collected if they are very rare.
Poor; these are not just smooth disks but actually identifiable coins. However, the list of shortcomings can be extensive. A few coins will still retain value over and above the metal content but they would have to be pretty rare.
Fair; heavily worn but with readable legend and major points of design identifiable. It would be reasonable to say that the vast bulk of 20th century coins in this condition are worth no more than their metal value.
Nearly Fine (NF); midway between fair and fine. Coins in this grade, although better than fair still show heavy wear. The legend however should be clear and bold without any partial loss of lettering which can sometimes be seen in the lower grade.
Fine (F); Fine coins show considerable wear to all raised surfaces. Some detail should be visible on the designs and some of the main hair volume should be visible on the monarchs head; not individual strands but maybe a parting or signs of head-dress. Many of the coins in your pocket even after just 30 years or less of normal use would probably be Fine or less.
Good Fine (GF); Intermediate grades are widely used but not quoted in price guides. In this case, Good Fine is better than Fine but not as good as Nearly Very Fine. A similar definition applies to all other intermediate grades
Nearly Very Fine (NVF); follows the pattern set above.
Very Fine (VF); a coin with some wear to the highest areas of the design but which has seen limited circulation. More hair detail is evident than in fine and also detail on the other designs. Just as an average guide a coin that has been in normal circulation for approximately 5 years may qualify for VF status.
Good Very Fine (GVF)
Nearly Extremely Fine (NVF)
Extremely Fine (EF); a coin with little sign of being circulated. There may be only the slightest wear to the highest areas and minimal scratches and other marks. Often some of the mint lustre is visible on coins of this grade. As a rough idea a coin in your change would probably be EF if it had been lucky and had been minted just a year ago.
Good Extremely Fine (GEF); just the merest hint of wear frequently only visible under a magnifying glass. Coins in this grade often display mint lustre.
About Uncirculated (AU); these coins do not display wear but the grade is not as stringent as plain uncirculated. Coins may have lost some or all of their lustre or may have rather more bag abrasions than a coin described as being in uncirculated condition. In my opinion most coins advertised as uncirculated should really fall into this category. For copper and bronze coins, I quote a percentage of lustre, so you will see such grades as GEF30 (a coin in GEF condition with 30% lustre spread roughly equally over both sides of the coin) or AU50/75 (a coin in About Uncirculated condition with 50% of lustre on the obverse and 75% on the reverse). I am incidentally, indebted to Michael Gouby for inventing this method of grading which has proved invaluable to copper and bronze collectors over the last two decades.
Uncirculated (Unc); as the name suggests, the coin should be as it left the mint with no signs of circulation or wear. Not necessarily perfect though, because coins can pick up scratches and what are known as bag marks during mass production and contact with other coins at the mint. With base metal coins, virtually all of the lustre should still be present and in this condition, the coin is described as brilliant uncirculated (BU). In many ways the description uncirculated is not satisfactory as it makes the presumption that the coin has never been handled as a unit of currency, but clearly this cannot be proven. What we mean therefore is appears to be uncirculated. One prominent dealer uses the term Practically as Struck (PAS) as an alternative, which certainly has its merits but for the time being we are stuck with what is usually an untruth.
Fleur de Coin (FDC); this is the term usually employed to describe proof coins which are technically perfect and is perhaps the most abused of all the coin grades. In my view coins which have toned, however slightly, or have any marks whatsoever should not be described as FDC. For this reason, I describe the vast bulk of proof coins simply with the word Proof and list any shortcomings in the text.
For further information on coin grading, please see my book, The Standard Guide to Grading British Coins 1797-1970 (http://www.amazon.co.uk/Standard-Guide-Grading-British-Coins/dp/0948964839/ref=sr_1_1?s=books&ie=UTF8&qid=1284378230&sr=1-1)