You have an imitation of the most celebrated US rare coin: the 1804 silver dollar. Too bad it is not real. There are only 15 genuine coins known to exist.
In the US we have a law that says all counterfeit collectibles must be identified with the word COPY. In China, they have a similar law, but only for Chinese coins. The crooks in China are flooding the market with all sorts of non-Chinese coins without the word COPY. They were recently outlawed on eBay, but they are still playing havoc with coin collecting. Sooner or later China will grow up as a nation and put a stop to it. But right now it is a real problem for collectors. And China is not the only culprit.
It is often possible to identify a counterfeit coin simply by looking at it. The quality of the strike and the details in the design sometimes betray a counterfeit. But not always. Sometimes a professional coin authenticator is needed to separate real coins from fakes. These professionals use advanced techniques for their work, including specific gravity tests and microscopic examination.
Another good indicator of authenticity is weight. An accurate scale, often available at a jewelry store, can immediately detect off-weight coins. A genuine 1804 silver dollar weighs precisely 26.96 grams.
With the advent of the COPY law, known as the Hobby Protection Act, interesting new area of coin collecting opened: Legal Reproductions. With COPY tucked neatly into the design, entrepreneurs like respected numismatist Ken Potter started producing coins that most collectors could never dream of owning. Now, for a few dollars, anyone can own an 1804 silver dollar that looks absolutely fantastic. You can see Ken's treasures at his web site Rare Coin Reproductions.
Stack's Bowers Galleries and many other international auction houses, runs major numismatic (coin collector) auctions with genuine silver dollars and hammers them down to the tune of hundreds of thousands of US dollars.
You can see the comparison in the picture below.