Well, mine has got more green than purple, so I guess it's more of a Barney with the colour proportions reversed. But hey, but let's not nitpick, I'll just call him Barney from now on anyway .
Great Marcus Zumbly! Love the green patina! Very Attractive! Here is a Marcus of mine. It is one of my favorites despite the scratches. Marcus Aurelius, AE Dupondius, 149 AD, Rome. O: M AVRELIVS CAESAR AVG PII F, Bare-headed, draped head right. Rx: TR POT III COS II, Clementia standing to front, head left, holding patter, holding out folds of robe; CLEM in exergue. SC in fields. 26 mm diameter and 11.08 grams. British Museum Catalog volume IV page 305 but with obverse legend a4. Colchester Museum has an example: accession number is 2006.71.143.
I only have one Marcus Aurelius and it is a well used Sestertius... the work-horse coin of the day! RI Aurelius Marcus 161-180 AE Sestertius S-C Obv-Rev.jpg But since I enjoy collecting Roman Republics, I liked comparing the Sesterius (AE) of the Empire vs. Sestertius (AR) of the Republic... Roman Republic Silver Sestertius compared with a Empire Bronze Sestertius... Marcus Aurelius' Wife Faustina II Junior... RI Faustina Jr 161-175 CE Ar Denarius m Marcus Aurelius 17-1mm 3g O-R.jpg
I only have this one CONSECRATIO that shows up in my files: RI Carus 282-283 CE AE 18mm Consecratio Flaming Alter Obv-Rev.jpg
stevex6 posted: "That OP-coin "rocks!!" The green patina with the purple globs is awesome!!" I agree, so does Zoisite!
So, again, noob questions. Trying to learn and understand: Is the green considered good? It seems everyone is quite positive about the OP's coin, and have posted a lot of green coins. Coming from the US (modern) side of things, when I see a green copper coin it is highly undesirable and should probably be thrown back. What caused the purple spots on the reverse? To me, they seem quite unattractive, but again, people are seeming to like them? I really like the portrait on the obverse.
Dark, green, "aged patina" is very desirable on bronze ancients. It adds to eye appeal and helps "seal" the surface. You already know what caused it.
Naturally formed patina protects our ancient bronze coins. In every instance, a nice patina will also increase (and sometimes greatly increase) its market value because collectors of ancients just like how they look. Conversely, a coin that has been stripped of this patina will lose appeal to the eyes of most collectors and hence value. Here's a page which covers the basics of patinas quite well: http://www.calgarycoin.com/reference/grading/patina.htm The purplish patches on my coin are what are left of raised mineral lumps formed by the corrosion of the copper in those areas. The coin was "smoothed" to make the surfaces more even. Most collectors would probably consider large mineral lumps sitting on top a coin to detract from its appearance, especially so if they obscure parts of the coin's design.
I have a feeling that day will be coming (in a few weeks? ). I received notification that my coin from NN44 shipped yesterday.