I have this tetradrachm of Antiochus III for some time. I never really gave a thought about it, bought from a very well known vendor and had never see anything on it to make me doubt it's authenticity. So basically my question is not about the authenticity but as I came back to the old listing I realized the weight stated is 16.35. I weighted it my self also and it was right. So my question would be what is the lowest a tetradrachm can get regarding the weight. Is it the condition that made it underweight?
During the Hellenistic period, a reduction in the weight of the tetradrachm is observed. from "LES ÉTALONS MONÉTAIRES GRECS : UNE INTRODUCTION" - Frédérique Duyrat 2014
Ancients can be low weight for various reasons, but I think the weight of your tetradrachm is fine. There's some porosity and that probably explains most of the lower weight, but it is a nice coin with what looks like an interesting countermark on the obverse.
In answer to @Basileus Antialcidas I looked at quite a number of Tetradrachms of Antiochos III offered for sale on the CNG web site and I can make the following observations based on looking at some 80 coins 1. One has to take into consideration that Antiochos III reigned for something like 35 years and employed numerous mints some long serving but some very temporary to service his needs. 2. My methodology is actually rather crude. I only looked at the weights I di not factor anything else into my equations. Things like wear or corrosion I only noted if they were severe. Some of my numbers though a very small percentage may actually be duplicated. Okay so what did it find? Pleas note all numbers are in grams A. I only saw two that were at 17.2 or higher B. The vast majority appear to weigh somewhere between 17.10 and 16.85. C. There were a few in the 16.65 to 16.55 range. Even fewer at 16.54 to 16.40 D. I did find 4 that were light weight. They were 16.39 16.32 (heavy corrosion) 16.19 16.40 (corrosion) and a real flyer at 15.66 Thus all I can say is this. Your coin is certainly at the low end of the spectrum but given its issues not outside the realm of probability. As for authenticity I see nothing that I find concerning with your coin however I really could not say that a coin is authentic based on a picture. Over all an interesting coin. Tetradrachm of Antiochos III Antioch 223-206 BC Obv Head right diademed Rv Apollo seated left on Omphalos 16.96 grms 27 mm Photo by W. Hansen
I always wanted to believe that on it's ear that seems like a counter mark could be a curse for the king to loose his hearing. It was a common practice back then to get a figure of someone and by scratching deeply parts of their body could make that part seek. I find it strange that this could be a counter mark or a test mark being so deep, precise and from what it seems from up close made by hand.
Thank you for your answer! Regarding authenticity I am quite confident as it was bought from one of the most well known ant trusted sellers and from my experience after close inspection it seems completely fine. The weight just got me wondering. Also I believe there must be some metal loss also from the very deep scratch on the ear that someone made during the ancient times.