Author Topic: Fake NGC slab danger  (Read 103840 times)

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Offline Hippanda

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Re: Fake NGC slab danger
« Reply #120 on: January 07, 2013, 08:38:48 PM »
Are there more tests you guys want me to do?


Just kidding....

that's enough... we now know it's just a cheap copper core plated fake.

Excellent job Sandac!  Maybe now we can use that analysis over and over to get these fakes off ebay? The more worrisome thing is the high quality fake NGC slab, and how the crooks now seek out certain certification numbers which have been deleted. The crooks are getting more sophisticated - be wary !

And again, does anyone have the contacts with the larger sellers who have seen these ie Bellevue Rare Coins? to ask and help trace the source of these fakes?
« Last Edit: January 07, 2013, 08:46:05 PM by Hippanda »
"He who speaks without modesty will find it difficult to make his words good."

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Offline dynamike51

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Re: Fake NGC slab danger
« Reply #121 on: January 07, 2013, 08:42:35 PM »
I made some more measurements:
Diameter, 21.8mm (should be 22mm)
thickness, 2.2mm
density, 8.9

I perform the density measurement by suspending the coin by a thin thread in water and measure the weight of displaced water.  Density is calculated by dividing dry weight (6.49g) by weight of displaced water (0.73g) =8.9.  Copper density at room temperature is 8.94 while gold is 19.3.  

I sent it off for XRF measurement and below is the report.  Summary:
2.03% gold
0.186% zinc
91.53 copper
6.26% nickel

So it is definitely a gold-plated Mazu replica.

Well, that's that.  Are there more tests you guys want me to do?



SANDAC,

Excellent work. !!! Hats off to you.   N34 :thumbup: :thumbup: :thumbup:

Offline silver222

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Re: Fake NGC slab danger
« Reply #122 on: January 07, 2013, 08:49:09 PM »
 :lol: ROFL... only thing funnier would have been a pic of Freddy with a chainsaw!

The density measurement is intriguing... I'm wondering if there is anyway to get a relative comparison without getting the coins wet (possibly by sealing each in an small airtite plasitic bag before the dip test?)  maybe the displacement measurement is too sensitive for such a test)

How about side by side measurements (real vs fake) of width, thickness and weight, along with side by side photos of any visible differences?

Offline Dr650rob

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Re: Fake NGC slab danger
« Reply #123 on: January 07, 2013, 09:27:43 PM »
Good job sandac
I didn't realize that place is close to were I live

Offline pandamonium

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Re: Fake NGC slab danger
« Reply #124 on: January 07, 2013, 09:33:03 PM »
SANDAC, is XRF that accurate?  It can show the composition of the coin?  Earlier posts here said the equipment cannot penetrate thick silver plate.  Can it penetrate thick silver plate?........

Offline Hippanda

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Re: Fake NGC slab danger
« Reply #125 on: January 07, 2013, 09:41:53 PM »
Poconopenn first raised the question of whether XRF can detect the type of thick silver plating that is heavily plated first then die stamped.  It is also called "clad", it is heavier than just thin cheap plating applied after minting.
It is thought that this thicker type of plating might be used on some Pagodas and some goldfish and other medals and may be able to pass casual inspection, since it leaves no coining marks, can be frosted, and maybe pass XRF as well since it is thick.
"He who speaks without modesty will find it difficult to make his words good."

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Offline Hippanda

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Re: Fake NGC slab danger
« Reply #126 on: January 07, 2013, 10:32:44 PM »
typo: meant to say "leaves coining marks"
"He who speaks without modesty will find it difficult to make his words good."

Confucius

Offline SANDAC

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Re: Fake NGC slab danger
« Reply #127 on: January 07, 2013, 11:24:47 PM »
The problem I try to solve is the non-destructive testing of fake coins in high quality slabs.  The fake NY Expo and Mazu are easy because they are different designs from the real ones.  A side-by-side comparison with NGC file photo is sufficient to demonstrate the differences.  For higher quality fake I'm thinking of three possible approaches:
1.  XRF.  As you can see, the XRF has excellent resolution to three digits, so it can accurately determine whether the metalic composition matches the original.  I also believe the thickly plated gold or silver coins are done with pure gold/silver.  So XRF can easily distinguish pure silver plated coin from sterling silver.  If I can get my hand on a NGC certified silver-plated Pagoda, I'll submit both plated and solid silver for XRF test to check out that theory
2.  Varieties guide.  Frosting and mirrored field variations are common in MCC.  So much so, we don't pay much attention to them.  However, a forger has the challenge of matching the subtle variety of the forged coin with the real coin.  So, the more we know about (and publish) the subtle differences and where to look in a coin, the more we are able to determine whether the purported coin matches the real one in NGC/PCGS file.
3.  DELETED grade.  If a slabbed coin is graded as "DELETED", it is definitely questionable and should be avoided.  I don't yet know whether it is a case of forger looking for deleted certification numbers to copy or NGC marked a coin DELETED after it being reported and verified as forgery.  I'm 1/3 of the way into compiling a DELETED database.  It doesn't happen that often, there are about 160 DELETED entries out of 33,000, so about 0.5%
4.  I'm sure there are a lot more good ideas out there.  An active fake coin forum, closer working relationship with eBay and NGC/PCGS, publish the slab weight for each certification number, etc.  We only have one poconopenn and we are all eager to learn from him, but I also think there are measurements and data that us non-expert can do or lookup and provide important clues about potential fake coins.  Forgery is a deadly poison to this hobby, we should all get involved.

Offline NBM

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Re: Fake NGC slab danger
« Reply #128 on: January 07, 2013, 11:56:28 PM »
Forgery is a deadly poison to this hobby, we should all get involved.
+1  N48

Offline pandamonium

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Re: Fake NGC slab danger
« Reply #129 on: January 08, 2013, 08:46:16 AM »
This is very important so I forwarded this page to NGC to get their opinion.  Hopefully they will respond to CCF and if they email me then I will post.  I was told in the past that one of NGC's highest priority is the accurate composition of coins/medals to avoid fakes.  NGC has the new equipment to detect metal in coins/medals.   Lets see what they have to say............

Offline panda88

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Offline SANDAC

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Re: Fake NGC slab danger
« Reply #131 on: January 09, 2013, 03:13:14 PM »
Thank you for reporting.  It is clearly not the same coin as shown in NGC file photo.

Offline cabaretvolt

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Re: Fake NGC slab danger
« Reply #132 on: January 09, 2013, 03:30:21 PM »
ngc should add an additional # on the description label written in ink only visible under UV lighting
whereby buyer of hypothetical can enter this additional number to verify that at bare minimum
any forger had at least had the authentic coin in hand at one point

this would at least help make it more of a pain in the ass for forgers

although i really havn't thought this thing through very far and might
actually create more problems than solves  N20
« Last Edit: January 09, 2013, 03:33:43 PM by cabaretvolt »
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Offline panda88

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Re: Fake NGC slab danger
« Reply #133 on: January 14, 2013, 12:18:08 PM »
I have a question. I have won the auction from 1 of the seller in Ebay. But few hours after that I received the message from Ebay:
Thanks for your interest in this listing:

281048133796 - 1989 CHINA GOLD 1/2 OZ 50 YUAN GEM BU SEALED

We're sorry to tell you that the item isn't available for purchase anymore. We removed the listing because it likely fell into one of these three categories:

-- The listing doesn't follow eBay guidelines.
-- The item isn't allowed on eBay or can only be listed under certain conditions.
-- The listing contains pictures or words that may have violated copyright or trademark rights.

This is disappointing for everyone, but sometimes it's an action we have to take to protect you as a buyer.

Important: If you won the item and haven't paid for it yet, you don't need to complete the transaction. If you've already paid for the item, we encourage you to contact the seller to get more information about the transaction. If you don't receive the item, your purchase price plus original shipping may be covered by the eBay resolution proces.

That mean the seller sell the "FAKE COIN " AGAIN ?? . Thanks

Offline panda88

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Re: Fake NGC slab danger
« Reply #134 on: January 26, 2013, 09:21:39 PM »
one more this one look worst.
w.ebay.com/itm/1989-Gold-Panda-coin-25-yuan-NGC-PF69UC-18TH-NY-EXPO-1-4-oz-999-5-K-Mintage-/200885722488?pt=US_World_Coins&hash=item2ec5b8dd78