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 Replies: 28 / Views: 18,910 |
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Pillar of the Community
United States
1812 Posts |
When I used to purchase scrap gold & silver over 15 years ago, I could not depend on the different acids required for gold, and purchased a $600.+ electronic gold tester... As for Silver, my only option was to file a small section of the object needing testing, then place a drop of Silver Acid on the file mark, and check the color chart... I never cared for that type of testing on Silver as it ruins coins... I am curious how the Silver tester tests for finess and plated silver, and its accuracy...  |
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Pillar of the Community
United States
1156 Posts |
from http://www.sigmametalytics.com/information.htmlQuote:
The Precious Metal Verifier is used to measure the bulk metal in a bullion bar or coin and ensure that the metal matches the electrical characteristics that would be expected of it....Using electromagnetic waves that penetrate deeply into the coin or bar, plating and surface features are largely ignored, and the main body of metal assessed. Edited by jgenn
01/08/2016 2:08 pm
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Moderator
 Canada
10463 Posts |
Quote:
surface residues would present their own XRF spectra that might lessen the apparent eg silver content. Anything being of light elements, like some oxide crusts or organic matter are not even attenuated or detected by an XRF when it is running in "alloy mode" software. Most bench top XRF instruments have captan (mylar) tape over the beam source and detector, to protect them - the source beam and returned energy passes right through it... "Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search." -- J. Robert OppenheimerContent of this post is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. See: http://creativecommons.org/licenses...0/deed.en_USMy eBay store
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Moderator
Canada
10463 Posts |
Quote:from http://www.sigmametalytics.com/information.htmlQuote:
The Precious Metal Verifier is used to measure the bulk metal in a bullion bar or coin and ensure that the metal matches the electrical characteristics that would be expected of it....Using electromagnetic waves that penetrate deeply into the coin or bar, plating and surface features are largely ignored, and the main body of metal assessed. A ha!! So it is a fancy resistivity meter... "Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search." -- J. Robert OppenheimerContent of this post is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. See: http://creativecommons.org/licenses...0/deed.en_USMy eBay store
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Moderator
Canada
10463 Posts |
Also, bear in mind that ancient hammered silver coins and annealled/rolled/ struck silver coins that are not pure silver, will have enhanced silver values at the surfaces of the coin. X-Ray beams in XRF analysis do not penetrate coin surfaces beyond a few microns. So in Canadian coins, .800 silver coins will often come back on the XRF as .900 fine or higher, and US .900 coins will read as sterling, or higher, silver coins. http://www.sciencedirect.com/scienc...583X04008316This is not necessarily understanding the analytical working of the coin tester, but also understanding what is occurring within the metal itself. "Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search." -- J. Robert OppenheimerContent of this post is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. See: http://creativecommons.org/licenses...0/deed.en_USMy eBay store
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Bedrock of the Community
 United States
11951 Posts |
I have been thinking about this thread and the questions and information
being posted.
I do find information and questions very interesting.
I would like to post what I think this tester does for me.
It helps me decide if the item, coin or bullion, I am looking at
is what it is suppose to be.
The user guide does give examples of how the device might give a
false reading. When the coin might be real.
But
When I am involved in buying and selling coins and bullion, I need to be
confident the item is what it should be. If not I should not by it, even if
there is a chance it is real.
If there is a chance, and the item has good value, for example a gold coin.
Then we might take it off site for more accurate testing.
We have had fake gold coin that were gold, that we have taken to be
tested. We will end up buying the fake gold coin for the gold value, then
have it melted.
Sort of the same way of a coin where it could be one of two grades.
If it is close to VF or XF, a business should buy it as VF. When in the
business of making money ...you can't take chances.
With this tester, if it gives you a chance a coin is not real, than the business
should not take the chance of buying it as a 100% real coin.
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Pillar of the Community
United States
4085 Posts |
Quote:
How does it work?
I am not sure ... Sorry ... I just set it up and use it. I did read the user
guide, it did not state how it works. Just a little more detail on how these work - what they do is that there is a small colony of miniature elves that live in the machine. Each has a particular speciality such as gold, .999 silver, 90% silver etc. When you put the coin down, the appropriate elf bites on a small section of the coin and based on hardness and flavor is able to tell if the coin is real or not. This typically does not harm the coin although excessive testing may cause TPG's to reject the coin as a details coin. This is typically indicated as on the slab as either "Bite Marks" or "Elved". And now you know...the rest of the story. |
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Pillar of the Community
United States
4963 Posts |
The price is mainly just because of labor costs (for the elves) and highly compressed food to keep them alive for years.
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Pillar of the Community
 United States
4594 Posts |
Their website talks about resistance, so here's how I think it works...
Under the center inside the ring is a coil of thin wire (an inductor). Calibration measures the resistance of the coil using a small alternating current. Then when you put the coin on the device, the current induces a small response in the coin, thus altering the apparent resistance. The difference or ratio depends on the precise metallic alloy.
-----Burton 50+ year / Life / Emeritus ANA member (joined 12/1/1973) Life member: Numismatics International, CONECA Member: TNA, FtWCC, NETCC, EveryCountry (online) coin club Owned by three cats and a wife of 40+ years (joined 1983) Author: 3rd Edition of the Sample Slabs book, https://www.sampleslabs.info/ |
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Valued Member
United States
345 Posts |
Did I see that it could also "test/identify" the age of the metal content, based on historical data I presume?
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Valued Member
United States
77 Posts |
For those of you familiar with operating a metal detector there are some similar processes in play with the PMV. As the metal detector's coil passes over a coin and the coin disrupts the electromagnetic field, the response is "read" by the detector's processor and displays a numerical or variable tone reading to alert you to the targets possible composition. Metal detecting in the field becomes a mix of science and art-form (skill and experience) of the detectorist. Too many variables such as soil composition, moisture, corrosion, depth of target, angle of target play a big roll in accurate readouts and identification. The PMV has the advantage of operating in a controlled environment and therefore its readings are very consistent against an internal stored library of resistivity values. One unit finds your money..the other unit saves you money!
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Pillar of the Community
United States
900 Posts |
I'm going to awaken this dormant topic and ask if GR58 is still pleased with this product.
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Bedrock of the Community
United States
20753 Posts |
Maybe someday a company will make one a lot cheaper.
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Replies: 28 / Views: 18,910 |
First Page
Posted 01/08/2016 2:07 pm
