Weighing and Grading Sovereigns

[Auric1253]

I have always thought that the grading of coins must be somewhat subjective, except in the case of a coin known to have had no circulation (eg has come straight from the mint). Then,  the description ‘uncirculated’ seems fair.

Lately I have been wondering, at least in the case of sovereigns (whose uncirculated weight is tightly specified at 7.988 grams), whether a more objective measure might not be the weight of the coin.

But this prompts the question of how easy it is to accurately weigh a sovereign.

Does any member with a digital balance that is specified to .001g have any experience of the variability of weights of uncirculated sovereigns? Do they mostly come out at 7.988g?

[Xander]

The pure gold content is 7.32240 grams.

[Auric1253]

 Yes, if the freshly minted sovereigns consistently contained 7.32240 grams of pure gold then the coins would have to consistently weigh 7.98807 grams.

My question is this consistency plausible or confirmed my members weighing their uncirculated coins.  

[Booky586]

The royal mint will have very tight manufacturing tolerances for their coins, for obvious reasons. They will have the definitive answer, but I don't know if they would share the information. Although the link below doesn't answer your question fully, it does glean a little more information:

 

[sovereignsteve]

On 26/01/2020 at 13:53, Auric1253 said:

Does any member with a digital balance that is specified to .001g have any experience of the variability of weights of uncirculated sovereigns? Do they mostly come out at 7.988g?

I don't have access to an analytical balance now I'm retired but when I did check modern sovereigns using one calibrated to 4 decimal places, they were all well within the quoted specification.

[Auric1253]

Many thanks to Steve and Booky for their replies.

I have now acquired a digital balance whose readout in grams goes to 3 decimal places (ie 1mg res.) and I have to assume that is reasonably accurate (at least in the range 1 gram to 50 grams)

The reason for that is that when I weigh calibration weights either singly or in combination of stamped values 1g, 2g, 5g, 10g, 20g, 50g, the display reads repeatedly the exact value you would expect (or within 1 milligram of that).

I don't see how that could happen if the weights were not very accurate or balance not accurate.

Now here comes the mystery. When weighing sovereigns (of diverse dates) that I can see are uncirculated or are known to be uncirculated, I consistently get a weight of 7.998 grams, a deviation of 10 milligrams from the official figure of 7.988 grams.

It is as though the Mint has added an extra 10mg for good luck .

Any thoughts?

PS I can give identifying details of the model of scales that I bought if anybody is interested.

PPS the weight of  modern 50p coin such as you will find in your change is somewhat variable, though officially 8 grams . But it wasn’t difficult to find one that gave exactly the same read out on the scales as an uncirculated sovereign. So that gives a cheap low-cost check you can carry around in your pocket. to determine if  a sovereign has lost weight from wear.

[marie123]

My sovereigns are not uncirculated but all in fairly good condition (I am newbie so not yet able to give accurate grades). These sovereigns were all purchased by a family member at the time they were issued and have been passed down to successive generations.  The earlies sovereigns belonged to Great Great Great Great Grandfather of the current owner. The weights of my sovereigns are as follows:-

year	monarch	soveign/half	weight g	minted
1874	victoria	sovereign	8	london
1887	victoria	sovereign	8.009	london
1889	victoria	sovereign	7.958	australia
1890	victoria	sovereign	7.988	australia
1890	victoria	sovereign	7.982	london
1892	victoria	sovereign	7.986	london
1893	victoria	sovereign	7.988	london
1893	victoria	sovereign	7.97	australia
1893	victoria	sovereign	8	australia
1895	victoria	sovereign	7.974	australia
1899	victoria	sovereign	7.943	london
1900	victoria	sovereign	8	london
1901	victoria	sovereign	7.976	london
1902	edward VII	sovereign	7.986	london
1911	george V	sovereign	7.983	london
1911	george V	sovereign	7.967	london
1912	george V	sovereign	7.975	london
1914	george V	sovereign	8	australia
1925	george V	sovereign	7.98	south africa
1963	elizabeth II	sovereign	8	london
1911	george V	sovereign	7.992	london
1907	edward VII	sovereign	7.991	london
1911	george V	half	3.972	london
1911	george V	half	3.965	london
1907	edward VII	half	3.961	london
1894	victoria	half	3.946	london

[sovereignsteve]

What a great collection, photos would be nice😉

[Skyfiller]

For my 2021 sovereigns I have weights of 7.995, 7.988, 7.990 & 7.982

[Auric1253]

Very interesting, Skyfiller.

Yes, my impression is that with modern bullion sovereigns bought directly from the Royal mint they can easily be overweight (ie weigh more than the official specified weight). 

However with (for example) Elizabeth ll Young Head coins, that by eye appear uncirculated, I find that their weights are consistent and have never encountered one coming out as overweight.

However, returning to my original question about grading - has anybody weighed a coin that they would confidently grade as EF or VF or Fine. and can say how much less than the official weight (in percentage terms) the coin was. 

Recently  was offered a 1817 George lll half sovereign, which I thought was at least Fine grade, and on my scales this came out as 3% underweight. The seller wanted £260 for it and with little  experience of such early coins, I couldn't decide if that was a good price.

[stefffana]

35 minutes ago, Auric1253 said:

Very interesting, Skyfiller.

Yes, my impression is that with modern bullion sovereigns bought directly from the Royal mint they can easily be overweight (ie weigh more than the official specified weight). 

However with (for example) Elizabeth ll Young Head coins, that by eye appear uncirculated, I find that their weights are consistent and have never encountered one coming out as overweight.

However, returning to my original question about grading - has anybody weighed a coin that they would confidently grade as EF or VF or Fine. and can say how much less than the official weight (in percentage terms) the coin was. 

Recently  was offered a 1817 George lll half sovereign, which I thought was at least Fine grade, and on my scales this came out as 3% underweight. The seller wanted £260 for it and with little  experience of such early coins, I couldn't decide if that was a good price.

So, that coin was only 3.87g? Missing 3% from initial weight is in my opinion a little too much, even keeping in mind it is a 205yrs old circulated coin.

But my knowledge about this topic is very limited as well and maybe I'm wrong.

 

[Borys]

Have similar question in relation to GB 5 sovereigns of 1887 weighted 40.19g. Is it possible to have so big overweight? Comments appreciated

 

  

[SidS]

According to the 1868 written article I posted a link to on another thread it wasn't uncommon for sovereigns struck in the Victorian era to be either struck underweight or indeed on occasions overweight. I assume the tolerances of the time were within a window of acceptability therefore.

In modern practice a sovereign should be more or less exact. I have owned sovereigns that were exactly 8.00g in weight of this period. I have also owned a 1927SA that always weighed 8.01g regardless of how many times (or different scales) I used. Nothing about that coin suggested it wasn't genuine.

I believe therefore it's less common but totally feesible to have a few that tend to the heavier end.