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Author	Replies: 6 / Views: 1,086
nilgandi New Member United States 6 Posts	Posted 07/21/2015 5:10 pm What is around the coin near the edge? Report this Post to the Staff

chequer Pillar of the Community Canada 4227 Posts	Posted 07/21/2015 5:30 pm The dark parts? Toning, the silver is reacting with the environment it's stored in. If you don't want toning, you need to get rid of any humidity. Report this Post to the Staff
jbuck Moderator United States 188440 Posts	Posted 07/21/2015 5:32 pm to the Community! Looks like typical toning for silver coins. Coin Collector Since 1978 Avatar Old Avatar 7070 Eisenhower Australia Canada World CCF Members on eBay CCF eBay Search Engine Report this Post to the Staff
dsfreeworld Pillar of the Community United States 4337 Posts	Posted 07/21/2015 5:42 pm Nice looking coins. that mottling you see setting in is the silver sulfide tarnishing. If you REALLY want to know the details just research the phenomena "Thin Film Interference" and that will tell you from a scientific standpoint the "toning" you see happening. Good luck! Report this Post to the Staff
paralyse Bedrock of the Community United States 12057 Posts	Posted 07/21/2015 7:13 pm 4Ag + 2H2S + O2 = 2Ag2S + 2H2O (silver coin, hydrogen sulfide from paper, atmospheric oxygen = silver sulfide + water vapor) AKA "toning" if you like it, "corrosion" if you don't (note that like aluminum oxide or copper carbonate/verdigris it's a protective patination, not a destructive loss of metal like iron corrosion) In other words, it's the natural product of the silver surface of the coin reacting with the proof set case in which it is stored. Some collectors enjoy the look, others don't. Given a long enough exposure in the right environment it can color the whole coin on both sides, sometimes with beautiful iridescence, sometimes with ugly dark black tarnish, or golds, greens, blues, and everything in between. Welcome to the forums :) Member ANA - EAC - TNA - SSDC - CCT #890 "Most of the things worth doing in the world had been declared impossible before they were done." -- Louis D. Brandeis Report this Post to the Staff
Scropper CCF Sponsor United States 702 Posts	Posted 07/21/2015 10:11 pm Cool answer, paralyse! Report this Post to the Staff
paralyse Bedrock of the Community United States 12057 Posts	Posted 07/21/2015 10:28 pm I must be the only kid in school who asked my AP chem II teacher why silver tarnished. He was a cool guy, though. Taught us how to make soap, ice cream, flash powder, and carbide-fueled potato cannons out of coke cans and lighter fluid. Member ANA - EAC - TNA - SSDC - CCT #890 "Most of the things worth doing in the world had been declared impossible before they were done." -- Louis D. Brandeis Report this Post to the Staff
	Replies: 6 / Views: 1,086

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