2015 .999 britannia thinner than other years?

[stackerp5]

Hello! Relatively new to stacking and TSF. I have some questions regarding britannia size and tarnishing. Probably unecessary but will put my mind at ease...

First time buying a couple of backdated/pre-owned britannias from the European Mint.

I received them normally as expected but noticed the .999 2015 britannias are slightly thinner than the other years. I looked up and they are supposed to have the same thickness of newer versions and they seem to have the same diameter. I attached a picture. Is this normal/expected? The metal content is around 31.2g. Picture comparison between a 2020 brit (top) and the 2015 brit (bottom).

One other question is regarding tarnishing. I received a 2020 coin with no milk spots but slightly tarnished black-ish (see picture) how can this happen? Some of the coins had this orange/brownish light stain also but couldn't get a clear picutre under this light.

Coins pinged well although the ping seemed to vary slightly from coin to coin (probably my error) and I bought calipers to measure the coins to be sure of measurements.

[mrrick]

the tarnish is oxidation

it can be removed by the bicarbonate of soda trick 

it usually happens when coins are exposed to air , hence why the coin tubes are supposed to be air tight 

[kimchi]

1 hour ago, mrrick said:

the tarnish is oxidation

it can be removed by the bicarbonate of soda trick 

it usually happens when coins are exposed to air , hence why the coin tubes are supposed to be air tight 

That's pretty extreme oxidation/tarnishing for a 2020 coin imvho, never seen anything as bad as that (not saying it can't/doesn't happen mind! ).

It's just bullion so I wouldn't mess about with trying to clean it myself.

2 hours ago, stackerp5 said:

I received them normally as expected but noticed the .999 2015 britannias are slightly thinner than the other years. I looked up and they are supposed to have the same thickness of newer versions and they seem to have the same diameter. I attached a picture. Is this normal/expected? The metal content is around 31.2g. Picture comparison between a 2020 brit (top) and the 2015 brit (bottom).

Mints give 'exact' specifications, but even the 'best' ones seem to have room for 'error' etc. I only learned this after contacting the Perth Mint (highly regarded in terms of quality and precision) about very slight differences in Kookaburra weights a few years ago.

The Royal Mint have a recent history of striking their coins incorrectly to give a wrong/wonky depth (some of the 2oz Queen's Beasts are fairly well-known examples).

If I were you I would get a set of scales (dimensions, ping test, magnet test alone are not enough if you want to be sure). I trust the European Mint myself, but imvho one of the best things you can ever do is not to feel 100% sure until you have performed a Specific Gravity Test along with the other checks. It's a great habit to get into to make sure you never have fakes (no matter where they come from).

Please let us know how you get on

[stackerp5]

6 minutes ago, kimchi said:

That's pretty extreme oxidation/tarnishing for a 2020 coin imvho, never seen anything as bad as that

Exactly why I asked. As a relatively new stacker (coming on two years) I never seen any of my coins get this tarnished within a year.

8 minutes ago, kimchi said:

The Royal Mint have a recent history of striking their coins incorrectly to give a wrong/wonky depth (some of the 2oz Queen's Beasts are fairly well-known examples).

Ah yes, thank you. Although the thinner coin is the 2015 version!

As you said, I will be doing a specific gravity test on the coins for sure. I have a precision scale and the weight was 31.2g which is within the range for britannias from what I know.

Thank you again for your help and comment! I will update this thread after having specific gravity tested them

[Bimetallic]

Do you have calipers? I bought a set after I started stacking. So while it looks like the bottom coin is thinner, looks can be deceiving. In particular, here, the bottom edge of the bottom coin might be sort of underexposed. It seems like there might be a bit more thickness to the coin that is obscured by the fuzziness or darkness of the bottom edge. Only way to be sure is to measure.

By the way, do you have any pre-2013 Britannias? I'm curious what the thickness is on those compared to the 999 versions. As you probably know, they were made of Britannia silver, 958 fine, so they weighed more than an ounce, kind of like American Gold Eagles. I think they have a different diameter, and I wonder if they kept the thickness constant.

[Bimetallic]

It's also possible that the difference in thickness, if there is one, is due to the rim only. Can you tell if the relief is deeper?

I'd clean the tarnish off for sure. The aluminum foil and baking soda method works extremely well for this type of tarnish, and is harmless to the coin, unlike silver dips and polishes. It's also dirt cheap.

After cleaning, I'd securely store the coins so that they never tarnish again. Do you know how they got exposed to air? Were they in tubes? It's unusual for bullion to tarnish when stored in tight tubes. If I leave coins in flips, which are not sealed, and throw them in a sock drawer, they'll tarnish in two months or so. Hard lesson. So I don't do that anymore – I keep them all in Ziploc snack bags (smaller than sandwich bags), or tubes. I also throw anti-tarnish tabs and strips into the bags and tubes. They're cheap, and they absorb the sulfur in the air.

[stefffana]

On 01/12/2020 at 21:59, stackerp5 said:

I will update this thread after having specific gravity tested them

Hi, @stackerp5!

Can you tell us how is doing your 2015 Britannia?

Have you done your specific gravity test?

I couldn't sleep well since December of 2020, asking myself about your coin...

Please, I can not wait your conclusion...!🤗

[stackerp5]

I bought a Sigma but my smooth brain forgot to analyse the coin! Please have some sleep my bert friend @stefffana and as soon as I get them out again i will post an update 😎✌

[James32]

3 hours ago, stefffana said:

Hi, @stackerp5!

Can you tell us how is doing your 2015 Britannia?

Have you done your specific gravity test?

I couldn't sleep well since December of 2020, asking myself about your coin...

Please, I can not wait your conclusion...!🤗

Business is slow?

[stefffana]

4 minutes ago, stackerp5 said:

I bought a Sigma but my smooth brain forgot to analyse the coin! Please have some sleep my bert friend @stefffana and as soon as I get them out again i will post an update 😎✌

Thank you!🤗

Good night!😜

2 minutes ago, James32 said:

Business is slow?

Yep.

[jackflash123]

5 minutes ago, stackerp5 said:

I bought a Sigma but my smooth brain forgot to analyse the coin! Please have some sleep my bert friend @stefffana and as soon as I get them out again i will post an update 😎✌

Hey @stackerp5 out of curiosity how much did you have to pay for a Sigma tester and if you don’t mind sharing where was it acquired from? Would be good to know the current price tag for such a testing machine.

[stackerp5]

6 minutes ago, jackflash123 said:

Hey @stackerp5 out of curiosity how much did you have to pay for a Sigma tester and if you don’t mind sharing where was it acquired from? Would be good to know the current price tag for such a testing machine.

Approximately £780 (after converting) with shipping included via DPD. Then VAT on top once it arrived in the UK (before delivery). 

If I'm not mistaken this is the link I used (link from my email/order confirmation): https://zetberg.com/sk/kupit/sigma-metalytics

[jackflash123]

1 minute ago, stackerp5 said:

Approximately £780 (after converting) with shipping included via DPD. Then VAT on top once it arrived in the UK (before delivery). 

If I'm not mistaken this is the link I used (link from my email/order confirmation): https://zetberg.com/sk/kupit/sigma-metalytics

Hey thanks so much for sharing. I have considered getting one of these, I know a few top forum members have them, and they are great for confirming the type of metal. I saw a post by @James32 who showed an image of a silver krug being tested, and the readout stated it was indeed a krug. I guess these testers can even verify the type of coin as well as the purity of the metal, is that a correct assumption? Maybe you or @James32 can confirm this for me and anyone else who is reading this post and is interested in the Sigma testers.

[stackerp5]

14 hours ago, jackflash123 said:

Hey thanks so much for sharing. I have considered getting one of these, I know a few top forum members have them, and they are great for confirming the type of metal. I saw a post by @James32 who showed an image of a silver krug being tested, and the readout stated it was indeed a krug. I guess these testers can even verify the type of coin as well as the purity of the metal, is that a correct assumption? Maybe you or @James32 can confirm this for me and anyone else who is reading this post and is interested in the Sigma testers.

I think the Pro models can detect that, but don't quote me on it. The standard version only detects metal content/purity up to a certain depth in millimetres. You can use calipers to measure the width and height of the coin to see if it's within standards provided by the mint.

On the standard version I own you can seleect different types of pre-loaded and calibrated coin purity ranges such as modern 999 or older 958 (i think) silver britannias. Or pre 1933 US gold coins and modern 22ct gold coins from different countries. Maybe that's what you are talking about. You select the type of coin you want to test, calibrate the sigma and place the coin on/under the sensor. If it falls in the bracket range, it's genuine. If it doesn't you can readjust the coin or turn it around etc to get a positive reading as the standard version isn't 100% reliable.

[James32]

I've pm'd @jackflash123 pics but will upload here too.

Testing ability of standard machine. 

[jackflash123]

Thanks to both @stackerp5 and @James32 for both your explanations and images sent in PM regarding this question.

its always good to get answers from someone who owns one and who knows how to use the machine. Better than any description on a website. Thank very much gentlemen 👍