No-one's yet identified your coin. It's an ancient Arabian coin, from the Sabaean kingdom (the biblical kingdom of Sheba) in what is now Yemen, imitating an Athenian tetradrachm but smaller. The lightning-bolt on Athena's cheek is a Sabaean letter, denoting the denomination; this is one "unit" (we don't know what the Sabaeans called their currency units). The coins also come in half, quarter and eighth-units.
I'm not skilled enough to know if these are counterfeits or not - it doesn't help that the original genuine coins are themselves imitations of other coins - but some modern counterfeits are noted on the zeno.ru page for these coins.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis