These ancient coins are amazing. The pictured silver (AR) tetradrachm comes from Athens, Greece and dates around 393 to 350 BC. To hold something identifiable in your hand from that long ago is really quite astounding. Ancient coin collectors do it all the time!
The owl and AOE inscription quickly identify Abdullatif's coin as Athenian. If you do a Google image search on 'coin from Athens' you will see hundreds of examples.
TETRADRACHM: roughly 22 mm diameter and 17 grams
DRACHM: roughly 10 mm diameter and 4 grams
Our main picture (upper right) comes from Munzhandlung Ritter GmbH in Dusseldorf, Germany. Ritter's coin is in great shape and is currently selling for over $1000 US dollars on the VCoins.com web site. If Ritter or another reputable coin dealer were to buy such a coin from you, he or she would pay roughly one-half the retail price, perhaps more if the coin is in excellent condition.
Note the symbol in Athena's cheek is probably a countermark, added after minting. Each of these coins stands on its own merits and values vary widely. Some very, very approximate values are:
worn: $400 US dollars approximate catalog value
average circulated: $800
well preserved: $1500
Counterfeits abound. The image to the right shows a well-executed fake. It is worth zero. The large photo near the bottom of this page is of a silver tetradrachm from Ira and Larry Goldberg in Beverly Hills, California, USA. It sold for $1300 US dollars in a 2014 auction.
It is absolutely critical for novices to ancient collecting purchase coins from well-known, fully reputable dealers. Our favorite web site for anti-counterfeit investigation is ForumAncientCoins.com.