Here's my example, the patina is solid and consistent, but there's a lot of surface corrosion. I don't know if it is a result of where these coins are mostly found, or maybe the fabric of the coins, but this sort of appearance is very common for the AVGGG issues in my experience. They are scarce enough and historically interesting enough that I'm happy to pick them up regardless. Purchased from the detectorist that found it, along with a very ragged Allectus and, oddly, a coin from Siscia.
I know exactly who these dealers are, too, and I avoid them for this reason thanks to the issue being discussed on this forum.
Yes, I also avoid several dealers, who seem to apply fake patinas, and/or fake desert patinas. Either that, or those dealers seem to repeatedly buy from unscrupulous persons, who apply the fake patinas. As mentioned above, those dealers seem to have way too many coins, which have the exact same patina, and/or the exact same desert patina. In my opinion, it really is a shame, that some persons choose to apply fake patinas, and fake desert patinas, to ancient coins. I consider fake patinas, and fake desert patinas, to be damage. It damages an irreplaceable ancient artifact, in my opinion. It is similar to tooling and smoothing, in my opinion. Sometimes, the fake patina and/or fake desert patina are reversible. But how many persons have the time, to try to remove a fake patina, or fake desert patina? Especially if the fake patina or fake desert patina are glued on, with epoxy. And, sometimes, the coin is damaged in the process of trying to remove the fake patina, if the coin hasn't already been damaged by the application of the fake patina. Like @DonnaML once said, I wish there was an "Ignore" button, so I could ignore certain dealers. EDIT : I deleted some of the text, and the photos, of this post, because I'm not 100% certain of my suspicions.
To me that just looks like different lighting and photography, not an applied patina. With some color correction in Photoshop I could get the bottom coin to look like the top.
@Jay GT4 I appreciate your interesting and useful comment, regarding my previous post. After thinking about it, I decided to delete the photos, and some of the text, in my previous post, because I'm not 100% certain of my suspicions.
Here's a sandy one. This one looks like the sand is natural, but the highlights are not. By that I mean that the coin appears to have once been almost fully covered in sand, and mechanical means were used to scrape the sand away. I guess it's not bad. Tooled, maybe, but not too offensive IMO.
I preferred the " Mountain Patina " that made a brief appearance Should have grabbed some of those given their rarity
GREEN DESERT PATINA OF CAMPANIA Campania CAPUA AE 14-5mm 216-211 Hera Oscan Grain ear Hannibal capital Italia SNG Fr 517 SNG ANS 219 HN Italy 500 EE Clain Stefanelli Campania CAPUA AE Uncia 216-211 BCE Diana Boar Hannibal capital Italia SCARCE Campania CAPUA AE Semuncia 216-211 BCE Juno Xoanon Hannibal capital Italia SCARCE