OK, kind of what I thought but just seemed like it might be something else since the detail is incredible. Wouldn't plating it add a layer and distort details?
The aluminums were dated 1974 and you aren't finding one in circulation. You have a plated 1973 as already mentioned. Even if there was a miracle and one was found in circulation, it is an illegal coin and subject to confiscation. So you would have to break the law, smuggle it out of the country, auction it off on the black coin market in Amsterdam risking your very life with the Ukranian mafia, take your suitcase full of Euros and buy diamonds. Bring it back "the old fashioned way" and sell the diamonds here. Then hide the proceeds from the IRS. Here's a gold plated 1960 I found metal detecting: