Copper coloured toning on a sovereign - what is this?

[Silverlocks]

The sovereign on the right has an appreciable copper colour - my google-fu doesn't really turn up anything much of interest.  Anybody know what's going on here.  Is it an uneven mix in the alloy?

[dicker]

There are variances (some recorded, others not) where Sovs are more copper or more gold.

You would need an XRF to make a determination - from @LawrenceChard’s posts, what seems to be the case is that very very small differences in the composition of a Sov can make big colour differences. (See previous posts by @LawrenceChard with XRF test results)

Best

Dicker

[GoldDiggerDave]

The likelihood there would not be a huge difference in the composition though there can be detectable variances. 
 

The one the left looks very questionable to me, (but that’s another matter)

coins can have very different lives, some staying in tubes or bags for the vast majority of the time or some that have been heavily circulated or just had a harsh life, some could have be subject to all manner of external factors, water, chemicals left out in the elements etc that can have a noticeable effect on the appearance of the coin…..just look at some change you have in your pocket.

 

 

 

 

 

 

[LawrenceChard]

11 hours ago, Silverlocks said:

The sovereign on the right has an appreciable copper colour - my google-fu doesn't really turn up anything much of interest.  Anybody know what's going on here.  Is it an uneven mix in the alloy?

You have not mentioned that they are different dates, and probably different mintmarks.

The second is 1911 to 1928, the first is 1929 to 1932.

The second could be any of the 7 mints, but unlikely to be Bombay, whereas the first cannot be London, and is most likely to be Pretoria, South Africa, but possibly Perth, or even Melbourne.

Details matter.

While you may not appreciate why, it helps to give all the information you already have before asking for further help or opinions.

In addition, the later coin has more wear, and looks as though it may have been polished at some time, while the earlier coin appears to have acquired some toning.

This page may help slightly:

https://goldsovereigns.co.uk/datesexist.html

Even though it does not relate to colour or alloy.

This page may help regarding alloys:

https://www.chards.co.uk/blog/analysis-of-alloy-content-of-gold-sovereigns/180

😎

[Silverlocks]

47 minutes ago, LawrenceChard said:

You have not mentioned that they are different dates, and probably different mintmarks.

The second is 1911 to 1928, the first is 1929 to 1932.

The second could be any of the 7 mints, but unlikely to be Bombay, whereas the first cannot be London, and is most likely to be Pretoria, South Africa, but possibly Perth, or even Melbourne.

Details matter.

While you may not appreciate why, it helps to give all the information you already have before asking for further help or opinions.

In addition, the later coin has more wear, and looks as though it may have been polished at some time, while the earlier coin appears to have acquired some toning.

This page may help slightly:

https://goldsovereigns.co.uk/datesexist.html

Even though it does not relate to colour or alloy.

This page may help regarding alloys:

https://www.chards.co.uk/blog/analysis-of-alloy-content-of-gold-sovereigns/180

😎

The one on the left is from 1930, Pretoria mint mark on the reverse, and the one on the right is London, from 1913.  These are the reverses.  The 1930 has appreciably more visible wear than the 1913, which is in fairly good condition apart from the strange colouration.  The camera doesn't really show it well, but the colouration mostly sits in the fields around the effigy, which is more the expected gold colour.  It's not immediately obvious whether this is some patina on the surface of the coin or colouration in the metal.  The copper colour is also evident on the reverse.

The colour rendition is better if you download the photos and open them in the photo viewer app that comes with Windows.  I suppose the exam question here (to those folks who have handled sovereigns in large numbers) is whether you have seen something like this before or have some idea what it might be.

1 hour ago, GoldDiggerDave said:

The likelihood there would not be a huge difference in the composition though there can be detectable variances. 
 

The one the left looks very questionable to me, (but that’s another matter)

What is it about the 1930 that makes you think it looks questionable?

Edited December 29, 2022 by Silverlocks

[LawrenceChard]

1 hour ago, GoldDiggerDave said:

The likelihood there would not be a huge difference in the composition though there can be detectable variances. 
 

The one the left looks very questionable to me, (but that’s another matter)

coins can have very different lives, some staying in tubes or bags for the vast majority of the time or some that have been heavily circulated or just had a harsh life, some could have be subject to all manner of external factors, water, chemicals left out in the elements etc that can have a noticeable effect on the appearance of the coin…..just look at some change you have in your pocket.

Good advice.

Many people miss the opportunity to learn about real coins by looking closely at their small change.

In my youth, I must have looked at millions of (old) pennies, literally.

This sort of real life experience can teach stuff you will not easily find in books or online.

😎

[Silverlocks]

1 hour ago, LawrenceChard said:

In addition, the later coin has more wear, and looks as though it may have been polished at some time, while the earlier coin appears to have acquired some toning.

 

The coins were taken through a light box arrangement that makes them look flat (one of @DrDave's).  These are some photos with different lighting.  The 1883 Vic I've added at the bottom has definitely been polished, and you can see the remains of the polishing around the lettering and the base of the effigy, which is not evident on the 1930. Unfortunately the raws are a bit over exposed, so the colour balance is not so good and they've come out way too saturated when I pulled the levels down. 1913 1930 1883

 

 

Edited December 29, 2022 by Silverlocks

[SidS]

1 hour ago, LawrenceChard said:

Good advice.

Many people miss the opportunity to learn about real coins by looking closely at their small change.

In my youth, I must have looked at millions of (old) pennies, literally.

This sort of real life experience can teach stuff you will not easily find in books or online.

😎

I heartily agree with this!