It is characteristics like the ones here that trick me regarding what to look for with the varieties of doubling coin characteristics. I’m still learning betweeen those varieties. This coin seems to have characteristics on obverse with my limited photographing skills (date, God, We) and reverse (states and rica). Is this a better coin even for a doubling consideration compared to my former submissions?
I'm not seeing anything. Also, your picture isn't good enough to really make any details out on the obverse that you are talking about. It's all blurry.
It's a nice 1946. I do see doubling in the date, but IDK if it is DD doubling. How come on a lot of these nice coins, there are those "carbon" spots? And what exactly is a carbon spot, and how do they get there?
OK I thought it was gremlins. Don't feed them after midnight. No matter what time it is, it is ALWAYS after midnight.
Glad you mentioned feeding times , I will quit feeding the gremlins /trolls completely so maybe they will just disappear. !! I am a fairly new member also but was advised not to pay much attention to the You Tube coin videos unless you happen to know that the developer is a well known good guy.
It is a reaction to the copper. Some are of the opinion that it must be CuO deposits, as that is a dark black compound. Others claim it is a sulfuration of the copper surface to CuS ( also a black material). If you have some chemistry background, read the wikipedia articles on these 2 compounds and then try this article , which is about as close to working with the surface of a copper coin ( silver would be similar in the process) but they used a thin film material to isolate results better. https://www.hindawi.com/journals/ijp/2009/304308/ The result part here is interesting: During formation of the layer on the surface of polycaproamide, all processes proceed in an open medium; therefore, it is not possible to avoid ambient effects. Since the surface of this layer is active, it adsorbs oxygen, water, and other contaminants. substitute 'coin surface ' for polycaproamide' and you see that the reactive surface can adsorb things known to cause environmental damage to coins. They uses XRF and XPS to analyze the surface compounds. The bonding ( being partially metallic bonding ( Cu), and partially covalent with the sulfur and oxygen involved , they get ratios of Cu1.9375S rather the Cu2S we see most in chemistry. These ratios are found in some minerals that contaminate copper ore. I think at this point that sulfuration of the copper surface occurs and then interact on environmental factors to cause black spots, which could be CuS alone , CuO, or combination. Certainly not carbon. I would hope others contribute, as this has been an argument for decades. Jim
I think the term carbon spot became a catch all for dark spots. Several things cause it but it's tough to know exactly what. I just started calling them spots.
Yes I didn't know if the carbon spots on the reverse of this 1946 were indeed carbon spots, or something else, that's why the parentheses. Desertgems post was helpful.
It looks like there is a finger print in the field above liberty,I could be mistaken though. It is a nice 46!
