| Author |
 Replies: 10 / Views: 2,100 |
|
|
Pillar of the Community
United States
597 Posts |
i see allot of supper nice red LWC but a carbon spot on them leaves them what? worthless? will the spot turn into more? what causes it? will the spot lead to corrosion? thanks guys I appreciate any and all answers.  |
|
|
|
Pillar of the Community
United States
1121 Posts |
"... Carbon is not involved in these surface finish anomalies and the
process is not oxidation (so often described as the chemical
process). The culprit is sulfur and the process is sulphatization.
Carbon spots are found inside diamonds [inclusions from
imperfect pressure during formation millions of years ago] ?
not on the surface of coins and medals. The proper term in
numismatics should be ? SULFUR SPOTS.
These dark brown to black spots appear on both copper
(including bronze) and silver coins (including silver clad).
These are formed, not with contact with carbon, but contact
with sulfur from the environment. The sulfur comes from any
variety of sources. The curing of rubber, for example, includes
sulfur by vulcanization (thank you, Charles Goodyear!). Thus
rubber should never come in continuous contact with coins and
medals." -http://www.coinbooks.org/esylum_v07n16a16.html
|
|
Moderator
 Australia
16816 Posts |
"Carbon spots", as neversuited quoted, aren't really carbon; they're just called that because they're black, or appear black against the background of a shiny coin.
They're usually caused by a droplet of water (or, more commonly, saliva from somebody coughing or sneezing) landing on the coin. A carbon spot won't spread, and shouldn't get worse - but there's no way to make them go away - even if you wait for the rest of the coin to tone the same dark brown colour, the spot will still probably be visible.
A carbon spot won't affect the technical grade at all, since it's just toning and not wear. It does, however, affect the market value. By how much can depend on the size, number and location of the spots.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
|
|
Pillar of the Community
United States
4846 Posts |
so if you spit on a coin and left it there, it can make the whole coin "tone"?
|
|
Moderator
Australia
16816 Posts |
I'd hesitate to say "yes", because it probably depends on several other factors such as temperature, humidity, atmospheric sulfur levels and on how much sulfur is in your saliva, which in turn depends on what you've been eating lately. I also don't want to say "yes" in case some darn fool out there reads this and decides to try it.   Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
|
|
Pillar of the Community
United States
594 Posts |
Edited by KenRingold
05/14/2011 2:19 pm
|
|
Pillar of the Community
United States
4846 Posts |
i was actually going to try it, LOL!
|
|
Bedrock of the Community
United States
20753 Posts |
You really don't even have to spit on a coin to see such reactions. But that is a method to experiment and see such results. Try using modern Cents, eat different types of foods and drinks, then either spit or cough or just breath on such coins. Then place on a window sill and allow to just sit there for a few months or weeks.
It is amazing how much differences you would see pending on what you eat. Lots of Onions or Garlic does a good job.
|
|
Valued Member
United States
183 Posts |
this a form of coin cancer?
|
|
Moderator
Australia
16816 Posts |
"Cancers" in metals are so called because they spread, almost as if driven by biological rather than merely chemical processes. Bronze disease on copper and bronze coins is a classic example. Carbon spots rarely if ever spread.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
|
|
Pillar of the Community
United States
3540 Posts |
Personally, I do not buy spotted Lincolns...period. Spots come under the heading of damaged coins to me. Unfortunate, yes.
Of note, when there is a row of the same date/condition coins, the spotted coins are rarely, if ever, marked down due to the spots.
|
| |
Replies: 10 / Views: 2,100 |
|
Posted 05/14/2011 12:03 am
