How can I check a slabbed coin is genuine?

[Booky586]

Slabbed coins have recently been added to my collection, purchased from both eBay and here on TSF.

I generally collect sovereigns, the older the better. When I make a new purchase of a loose coin I start by checking it's genuine. I don't have a gold analysis machine, so I'll check it's weight, diameter, thickness, and then a comparison check against another identical coin, to satisfy myself that I have the genuine article. However, with a slabbed coin, I can only check it visually, I can't check it's diameter, weight, thickness etc. I know the slab has a database number on the PCGS or NGC site, but merely checking the number is valid does not mean the coin or slab is genuine because I believe there are faked slabs (with duplicated database numbers) out in the marketplace. So I'm puzzled and would like to know:

How can I check a slabbed coin is genuine?

[BSquared]

AFAIK,  short of cracking it out and taking the measurements, etc. that you describe, you are relying solely on the database number from PCGS or NGC sites.  I've also had the same concerns, as one would think that it's easier to fake a plastic case and label, etc. than it is to fake the actual coin.

Hopefully, someone with more experience here will chime in.

[sovereignsteve]

It's a very good question.

It is a risk unless you know and trust the seller who says they have provenance on the coin, such as they were the one to send it for grading.

The best you can do is know the weight of a similar slabbed coin and compare the weight. Closely compare the slab to a genuine one but best is to have a HR photo on the grader website to compare. It is unlikely a counterfeiter will be able to get all points of alignment exactly right.

[jultorsk]

Apparently Sigma works also with capsuled/slabbed coins.

 

[5huggy]

Get to know someone with an XRF machine 😉👍

or get friendly with a bullion dealer who has one !

[sovereignsteve]

54 minutes ago, 5huggy said:

Get to know someone with an XRF machine 😉👍

or get friendly with a bullion dealer who has one !

can a XRF measure through a slab?

[matt1r]

As explained above, it shouldn’t be to difficult there are a few checks, the weight of course compared to a similar slabbed coin. I’ve found it can vary up to about 1.5g from either side of the extreme to the other - this was different years though not the same coin exactly. The pictures on ngc are the biggest help, marks on the coin if not a 70 should be the same and able to spot. If not the case you can compare, I have a couple with a spec inside the case and another which has an odd bulge but it adds up identical to the ngc stock photos. I highly doubt all these will be added so well to make it identical.

[Booky586]

3 hours ago, sovereignsteve said:

The best you can do is know the weight of a similar slabbed coin and compare the weight.

 

23 minutes ago, matt1r said:

the weight of course compared to a similar slabbed coin. I’ve found it can vary up to about 1.5g from either side of the extreme to the other - this was different years though not the same coin exactly.

This is the 1st route I followed, thinking I could add the coin weight to the slab weight and hit the target weight. The downside is I can't find a reliable slab weight reference yet. The weights I have found indicate they come in diferent weights, even from the same grading service. PCGS slabs look like they can vary from 25.8g to 31.6g per slab: https://forums.collectors.com/discussion/950711/holder-weights-and-etc

 

[matt1r]

10 minutes ago, Booky586 said:

 

This is the 1st route I followed, thinking I could add the coin weight to the slab weight and hit the target weight. The downside is I can't find a reliable slab weight reference yet. The weights I have found indicate they come in diferent weights, even from the same grading service. PCGS slabs look like they can vary from 25.8g to 31.6g per slab: https://forums.collectors.com/discussion/950711/holder-weights-and-etc

 

I guess it’s been an easier process for me collecting only ngc and only full and half sovereigns so far my tolerances are a lot easier to work out.

[Booky586]

3 hours ago, sovereignsteve said:

Closely compare the slab to a genuine one but best is to have a HR photo on the grader website to compare. It is unlikely a counterfeiter will be able to get all points of alignment exactly right

 

50 minutes ago, matt1r said:

The pictures on ngc are the biggest help, marks on the coin if not a 70 should be the same and able to spot. If not the case you can compare, I have a couple with a spec inside the case and another which has an odd bulge but it adds up identical to the ngc stock photos. I highly doubt all these will be added so well to make it identical.

This is good information. I've got a visual check, not necessarily on the coin but on any minor imperfection I can find within the slab and coin orientation.

If only all my slabbed coins had photos to check against on the PCGS website!

[5huggy]

16 hours ago, sovereignsteve said:

can a XRF measure through a slab?

YEP! my buddy in Cyprus uses a Niton "gun" for EVERYTHING! 😉👍

[Booky586]

On 07/07/2020 at 15:32, jultorsk said:

Apparently Sigma works also with capsuled/slabbed coins.

 

On 08/07/2020 at 09:38, 5huggy said:

YEP! my buddy in Cyprus uses a Niton "gun" for EVERYTHING! 😉👍

I've just looked up the prices for these analyzers and they don't come cheap but they do give you a guarantee that you have gold. Until I get one I won't be buying any more slabbed coins unless I can match it with a photo on the PCGS/NCG database. And given that the quality of photos on eBay are generally poor then no more slabs from eBay.