Hi As you probably know many ancient coins often have a sort of red and green spots. The green spot is called "bronze-disease". If you collect ancient copper coins, then you know what I'm talking about when I refer to the green and red spot. Now, I'm wondering whether this can be applied to fake coins? Is it possible to recreate the red/green spot on fake coins? Have you ever come across fake copper coins with red/green spot? Have a nice day folks
Bronze disease is similar to verdigris, although verdigris is a hard patina that is stable and actually protects the coin. Bronze disease is light and powdery and is unstable and can spread across a coin, eventually devouring it. Both are caused by the presence of chlorides, oxygen and water. Many fake ancients have artificially added patinas hat are just paint. https://www.cointalk.com/threads/bronze-disease.359159/
Any bronze can get BD. Put it next to an infected coin and it will get it. However, most spots of red and green, (darker green), are simply shades in the patina. Only the light, powdery green is BD. Spots are painted pretty well with paint. Put the coin in acetone, it will dissolve most paint but not harm a good coin.
It can be very powdery. Any fine powder can easily spread when disturbed. One of my first ancient coins, which I bought from supposedly reputable Dr. Klaus Kinsky (name disguised), was entirely light green. I naively thought it was just green patina but the coin was entirely covered in bronze disease. It soon contaminated all my other coins. As for red and green spots: Almost any type of patina can be chemically recreated by someone who really knows their chemistry.
Yeah, in my experience. I have had a coin with BD in a box, (unbeknownst to me), and a few others picked it up within a few months. They were all separately in archival 2x2s and from different purchases.
