Find numismatic directory. They are freely available online, usually on forums of coin collectors. These directories contain the latest information on the types of coins, their values (often with a specific value), as well as photographs with detailed descriptions. If the listing stated a coin like yours, carefully, ideally with a magnifying glass, compare them to the smallest detail. Counterfeits of the old days are often rough, so the difference will be noticeable even to a layman.
Contact foundry workshop, to determine cast or stamped coin. Ancient coins mostly chasing, but modern fake - casting. Depending on the type of metal (in the old days coins were minted from silver the other samples) and changing the weight, so be sure to compare the weight of the alleged ancient coins in the catalog.
Consider a coin under a microscope with at least 400-fold magnification. Genuine vintage coin will be visible to all the prints of time: corrosion, micro-chips, the delamination of the particles. Professionals during the inspection of the coins used stereo microscopes, which can determine the clarity of drawing.
If it is not possible to determine the authenticity and value of ancient coins yourself, try to appeal to coin collectors, Amateurs in specialized forums on the Internet. Note that for simple description of the coins no one will give a conclusion. Take a picture of the obverse and reverse (front and back side of the coin) in macro mode and put photos on the forum. Be prepared for the fact that you will be advised to conduct an independent examination in the case that the coin may be a greater collector's value.
Order your professional expertise with the help of spectral analysis. This method allows to determine the presence of different metals in the coin alloy and exposes even the highest-quality forgeries of antique. However, it costs expensive and is used mainly when we are talking about a rare instance.
Advice 2: How to determine the value of antique coins
Find some old coin, such as the 19th century, hardly anyone will think, and how much it costs now. For each coin there is the current market price, and it is formed of the same parameters.
What affects the value of the coin
First, the metal from which it is made. The most valuable are gold coins, which will certainly cost more than their weight in the transfer for the price of a gram of gold. Silver and copper coins less expensive, but can also cost a fortune in the presence of other components.
Secondly, it will be important the edition and the year of coinage. If it was only 100,000 coins and they were made 200 years ago, about 50-60% was probably lost, sunk or destroyed. So, presumably, there is a value. Information on print runs is in the directory coin collectors, where you can find and price.
Thirdly, very important is the current state of the coin. Of course, a very old coin in perfect condition there, but the ones that were released 70-100 years ago is still there. Mechanical damage from lower cost, as well as purification to give the best view.
The real value of coins
If you find some coin, do not think that it is insanely valuable, and you'll be rich in an instant. The probability of this coin by chance is negligible. Their search have to do purposefully, and even to know where to look. The common discovery may be coins of the USSR or copper coins of tsarist Russia.
The most expensive modern coin could be a commemorative "10 rubles" with the inscription of the Chechen Republic. Its value in the market of coin collectors comes to 10,000 rubles, and the average price of the remaining coins of the series does not exceed 200 rubles.
To know the value of coins, you need to be a numismatist, have at least a small collection and constantly replenish it. First you need to select the period for which you want to get coins, and then to study auctions and online ads selling. It so happens that the real value of the coin more, but it was sold cheaper. This suggests that the coin market is highly dependent on current demand.