Bag toned coins are awesome! And Manon did a good job describing them in words. But pictures tell the real story.
Most often you see bag toning on US Morgan silver dollars. These coins were poured into large canvas bags and left alone for decades in vaults at the mint. Impurities in the air and in the canvas bags caused chemical reactions with the silver in the coins, and this caused discoloration or, as collectors call it, toning. Some toning is really ugly, but some knocks your socks off! Rainbow toning, like the coins shown here, is the most popular. But all colors are possible. Bag toned coins display a characteristic crescent shape in the toning, formed by air blockage by neighboring coins in the bag.
More or less by default, toned coins are uncirculated, and most are made of silver. Circulation quickly wears away any toning present on silver coins, and copper, nickel, and gold coins tone much more slowly than silver.
As to value, most collectors shun toned coins, so their value is less than 'normal' specimens. However, there is a growing fraction of collectors who seek out nice toning, and these folks are willing to pay premiums for dazzling specimens. Exact evaluations are impossible because the of toning's subjective appeal, but, approximately:
- for dark or dismal toning, cut the normal value in half
- for nice, colorful toning, add 25% to the normal value
- for dazzling rainbow toning, double the normal value
These values apply only for the subset of collectors who like toned coins, so finding the proper selling method is important.
The coin in our primary picture comes from respected eBay seller john-strategies who specializes in toned beauties. Check John's web site for more examples of nicely toned coins.
As a final warning, counterfeit toning is easy to apply. Deal only with people you know and trust to deliver genuine pieces. Like all counterfeit detection, it takes years of experience to readily discern the fakes and choose only the authentic specimens.