I recently won a bulk lot of silver antoninianii from Leu Numismatik, my first time buying from that auction house. The vast majority of the coins were Gordian IIIs or Philips, with one or two empresses and other emperors. I was immediately struck by how light many of the coins felt. I even accidentally snapped one of the coins in half with very little pressure, like a cracker. A majority of the coins weigh <3.5 grams, and about 1/3rd weigh less than 3 grams. A few of them even weigh less than 2 grams. All of the Gordian ants I've had in the past have averaged closer to 4 grams, which makes me a bit concerned. I've taken a few pictures of some of the lightweight coins, including the edge of the one I snapped in half. Based on the pictures and the weight distribution, what do you think? Is crystallization a potential explanation, and does crystallization somehow lower the weight of the coin? (my assumption is no)
Hi @Volante, Crystalization does reduce coin weight. The snapped coin shows very heavy crystalization. -Broucheion
It's important to evaluate a coin in terms of its historical context. By the reign of Philip I, the "silver" coins had become very debased, to about 1/3 silver and 2/3 base metal. The various mints (Rome and Antioch) were cranking these things out as fast as they could to pay for military campaigns against the Persians. They used the dies -- especially the reverse dies -- longer than they should have and they became worn. The coins may not have looked all that good when they left the mint in the first place. Over the course of being buried -- or chemically cleaned after finding them -- some of the metal may leach out of the coin, leaving them underweight and with a porous or grainy surface. These coins are typically found in the condition of your example: brittle, porous and with soft details on the reverses. Pannekeet, Cornelis GJ. "A Theory on How the Denarius Disappeared and the Debasement of the Antoninianus." Academia.edu, www.academia.edu/3784962/A_theory_on_how_the_denarius_disappeared_and_the_debasement_of_the_antoninianus?auto=download.
Thanks for the reassurance all. I did think it a bit odd that these $30 coins would be faked, but the weight thing had me concerned. Didn't realize crystallization/leaching could reduce a coin's weight by as much as 60-70%.
