The oldest coin ever discovered was found of the island; efrosos. It is a Hellenic civilization coin, roughly 2700 years ago. And it was hand carved.
How do they know it's a coin? Couldn't it just be some guy had a chunk of gold (I'm assuming it's gold), and passed some time carving it? Maybe to wear or as a gift? I'm always curious how experts know what the original intention of an item was for thousands of years later. Heck, I can't figure out why every wall and ceiling in my house was painted mint green when I bought it!