thedrifter wrote:Thanks Tractotman. I think that will help me test my Canadian to my own satisfaction. Might be hard to convince an unknowledgable buyer of this but I believe
Engineer wrote:If somebody wanted to get really serious about sorting out the 80% coins, it should be possible to rig up something which would drop them the same way every time and then analyze the ring of the coin using a computer program to display the sound waves.
Bluegill wrote:Engineer wrote:If somebody wanted to get really serious about sorting out the 80% coins, it should be possible to rig up something which would drop them the same way every time and then analyze the ring of the coin using a computer program to display the sound waves.
A year ago somebody did just that at the Coin Community Forum.
http://www.coincommunity.com/forum/topi ... C_ID=79454
Bluegill wrote:At the old forum a member (I think it was fasTT) had an idea i kinda liked. Run them through the Ryedale. He mentioned manually loading them directly into the comparator.
beauanderos wrote:You guys just gave me an idea for another sales item... 1968 Canadian quarters priced at 50% silver melt price... you could just get lucky
henrysmedford wrote:I was at the coin shop buying some Canadian coin and the clerk was re looking them over for some missed silver and I said why not use a magnet as .5,.8 will not stick but all the rest of the .999 and steel will stick. He had not thought of that one.
uthminsta wrote:I've heard that. Makes sense, but that's just not good enough for my nit-picking brain. I would actually like to put one example of each .500 and .800 1967 dime and quarter in my Canadian collection, and be certain about which they are. I mean, I've got the 1968 silver dime, then the 1968 Ottawa nickel dime, then the 1968 Philadelphia nickel dime... so... I just gotta have 'em all!
hobo finds wrote:How do you know if you have the 80 or the 50?
This is a hard one. I had to pull Franklin's set out it see how it worked so if you take a 1953-1966 25 cent coin as a sample and do a ring test a 50 percent will not sound the same. See below. In 1968 half were .5 silver and half were nickel you can tell with a magnet as you can pick nickel up. So a 1968 silver would sound the same as a 1967 .5 silver. So if your sounds the same as the 1953 -1966 it is a .8 if it sounds the same as a 1968 silver it is a .5 .
From http://rg.ancients.info/guide/counterfeits.html
Ring test
Modern silver coins typically ring when you tap them with another coin or drop them on a table, emitting a longer-lasting, higher-pitched sound. Modern non-silver coins and ancient silver coins don't, emitting a shorter-lasting, lower-pitched sound. With ancient coins, the reason is crystallization (also called intergranular corrosion, reticulate corrosion, granularization, or embrittlement), which results when relatively pure silver alloys leach copper, lead, or other impurities over time, causing voids between the silver grains. You can often see small perpendicular ridges or swirling patterns on the surfaces of highly crystallized coins or feather-like crystals under magnification, though other times the crystallization is completely internal and invisible. The metal isn't actually becoming crystallized; rather, its crystalline structure is being revealed by natural forces over time.
To perform a ring test, balance the coin on the tip of your finger and tap it gently with another coin. With modern coins, you can wear a cotton glove to prevent fingerprints. You need to be careful you don't drop the coin or tap too hard. Highly crystallized ancient coins can break easily. If the coin emits a long resonating ring, like a bell, this indicates that it's a modern silver coin. If it's an ancient coin, this indicates it hasn't become crystallized, that it's likely a modern forgery, because crystallization dampens the ring. If the coin rings for only a second or two, this indicates it may be only slightly crystallized. If the coin emits a tink and doesn't resonate, this indicates it may be moderately crystallized. If the coin emits a thud, this indicates it may be heavily crystallized.
The ring test is far from foolproof, however. Sometimes forgers use the flans of authentic, though inexpensive, ancient coins to produce old-metal counterfeits of expensive ancient coins, but this typically happens only with rare or otherwise pricey specimens. Forgers can also create crystallized surfaces and interiors with both struck and cast fakes by playing with temperatures. Counterfeits made of new silver having small, thick flans don't resonate as well as larger, thinner coins. Counterfeits made of new silver may not ring at all if the flan is cracked, occluded with a gas bubble, or filled with another substance. Cast or electrotype counterfeits made of new silver also may not ring. Heavily alloyed silver coins made with significant amounts of bronze, lead, or other base metals will also not ring like pure or nearly pure silver coins. Nonetheless, a long resonating ring is a good indication that a coin is modern and struck.
henrysmedford wrote:The ring test works.
uthminsta wrote:Still wondering if anyone has tried the Ryedale method and gotten the results that they are confident with
uthminsta wrote:henrysmedford wrote:The ring test works.
My ears aren't smart enough I guess; I can't seem to tell the difference this way. Will try again. Still wondering if anyone has tried the Ryedale method and gotten the results that they are confident with.
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