Dear Mr. Berko:

About five months ago, you wrote a coin column and told about some of the coins you own and how some of the collectible coins have gone up in price.

I have 10 1916-D Mercury dimes (it’s a long story about how I got them in 2001) and took them to a coin dealer because I needed the money. I thought I would get at least $500 for each of them because they are still shiny and clean, because they have no scratches on the front and back and because the little ridges on the edges also have no wear. The dates, the words and the crisp facial features are easy to read, and each coin has been kept in a special protective holder since I got them. The coin dealer offered me $150 for each dime, and I said no. Then he raised the price to $170 and then $190, but I walked out. When I got these dimes from my brother, he told me that I should always be able to get at least $500 for each of them. Was my brother wrong? Please answer soon, because we need this money right away.

T.S., Cleveland, Ill.

Dear T.S.:

Holy Mary, Methuselah and Moses. I’d like to hear your long story of those 1916-D Mercury dimes, which may be the most counterfeited coins in the U.S. – and for good reason. Although not the rarest dime in U.S. history, it certainly is the most famous. First-year mint coins are almost always hoarded by collectors and the public, but for some reason, this 1916-D slipped under the radar. Millions of 1916 dimes were minted by the mints in Philadelphia and San Francisco, but coin collectors failed to notice that only 240,000 of these first-year dimes were issued by the Denver Mint. It must be the cold winters! The lowest-grade 1916-D coins can be bought for about $500. Your description of the crenelated edges, your use of the word “crisp” to describe the facial profile and your comment that there are no discernible scratches on the dimes suggest that these dimes could be worth between $5,000 and $20,000 each. That’s a lot more than $190 per coin.

As you would with diamonds – which are graded for clarity, cut, color and carat weight – you should have those coins graded to determine their value and to be certain they are not counterfeit. I’ve given you the contact number for Numismatic Guaranty Corp. (NGC), based in Sarasota, Fla. The people there will instruct you on how to get the coins to them. They will certify the authenticity of each coin, grade each coin (there can be as many as 20 different grades) and provide you with a reasonable estimate of value. After the coins are valued and graded, NGC will give you a certificate of quality that is respected by coin dealers from coast to coast. The folks at NGC are inestimably more dependable than the slippery sods at Standard & Poor’s, Fitch Ratings or Moody’s Investors Service, whose scandalous ratings contributed to the crash of the U.S. economy. The NGC process takes about a week, and the cost could be about $150 per coin. NGC’s seal of approval is important, and if you don’t have the fee, the people there still may be able to help you.

Most coin dealers are honest business people. Their integrity is the bond upon which their clients depend. However, this Illinois dealer really takes the cupcake. If your description of those coins is just 25 percent accurate, then the dealer you visited is an unprincipled, mendacious skunk. Let me know what NGC tells you.