1923 Half Penny

If he got the coin from Downies, he should sell the documentation from that sale along with the coin to prove provenance. Otherwise, the seller's guarantee is worthless.

Why would the seller want to keep the documentation without the coin?

I keep the documentation on all valuable coins I buy, in a separate folder, just for the reasons mentioned above.

Now you know why I like to see a valuable coin in hand before making a decision to buy, UNLESS the seller has a good reputation known to me.
In that case I would buy on approval if I want it, and keep the documetation anyway.

Downies, if they sell on ebay, would issue at least an official invoice and post that along with the coin on ALL lots, irrespective of value.

I think that this sort of hassle is not necessary on LOWER valued lots from ebay, with private persons, because less money is involved.

Even private people can sell high value items on ebay, but it is essential that they can prove the provenance of what they sell. I just don't buy that way.

Yep,it looks OK from my limited experience and knowledge but the Chinese fakes are exact copies of the master/donor coin.I read an article about 3 years ago,will post a link when I find it again,that a 3D image of the coin is created from a scan and a computer controlled copy is then created,the author didn't say how this was done or how they get the ageing and weight correct.However after holding a copy of a Australian 1933 Shilling in my hand all I can say is Buyer beware as they're excellent/very good reproductions.

The coin appears genuine, the seller has a good track record. My only issue is that he has overgraded the coin. I would only rate it Fine.

How can one anyone (even a TPG) possibly be able to detect an excellent Chinese counterfeit coin of ANY type when for example

a) a high resolution very high magnification picture has been posted on CCF to ID surface anomalies(incl. seams in the rims, cast settling points etc...),

b) the weight has been determined to be +/- .001 grams within spec.,

c) an acid test has been performed to detect the presence of precious metals(when applicable),

d) a magnet test demonstrated no attraction (for silver, gold etc),

e) the ring test's sound confirmed precious metals when applicable,

f) the tissue test confirmed 90% silver when applicable,

g) the thickness and diameter are within .001 of specs

These above characteristics are just some of the more apparent tests that one would think about when confirming the authenticity of 'any' coin(including ones with precious metals)

I just cannot understand how even a TPG can be 100% absolutely positive about a coin's authenticity when advanced computer imaging is duplicating a coin 1 for 1 for every single aspect to be measured.

In summary please help me understand how it is possible for even a TPG to detect coins manufactured like these.

mdpmedia

A neighbour of mine has access to a mass spectrometer. A pinpoint of metal shot off the edge is all that is needed to test for trace elements, and to compare the results against known genuine coins.

He also actually OWNS three electron microscopes acquired by disposal from his employer. His qualifications: pHd in materials science. He is often called before the courts to give evidence as an expert witness.

Wow Sel,

That is neat and the exact kind of informed and useful response I was hoping to receive.

Even though I briefly used these machines in college while pursuing my biology and chemistry degrees, that was several years ago.

I am not up to date with the improvements in these technologies and never thought to consider the applicability of these machines for use in coin authentication.

What do you think this gentleman would charge an interested third party for authentication of a valuable rare date coin having questionable traits?

Does he happen to be a CCF member who might be willing to give an in-house discount for brothers and sisters of the fold?

One might consider using someone like this in the event a TPG spits back a glaring grade error while producing one of their slabs etc...

mdpmedia

It is a race as always, counterfeiters come up with new ways to make the coin, we come up with ways to detect the new counterfeits.

Not sure if I'd ever buy this type of coin of ebay. I'd want the thing in my hand before I paid for it.

Speaking of which, sorry if this is against the rules, but Roxbury's has a couple of 23 1/2d's in their next auction in June. Also a couple of 30 d's.

Cheers
Pete