Coin Community Family of Web Sites
Like us on Facebook! Subscribe to our Youtube Channel! Check out our Twitter! Check out our Pinterest!
Username:
Password:
Save Password
Forgot your Password?


Welcome Guest! Need help? Got a question? Inherit some coins?
Our coin forum is completely free! Register Now!

Grime On Gold Sovereigns

 
To participate in the forum you must log in or register.
Author Previous TopicReplies: 9 / Views: 525Next Topic  
New Member

Germany
39 Posts
 Posted 07/28/2021  7:04 pm Show Profile   Bookmark this topic Add stgaudens to your friends list Get a Link to this Message
Hello,

I have noticed that some old gold coins have some kind of dark/black grime on the highest points of the design. This is extremely common with the british sovereigns.

I wonder: where does this grime come from? Why is it mostly located on the high points of the design? Why are so many sovereigns affected and not that many other coins?

Here are some examples:

https://auctions.stacksbowers.com/l...-gold-shield

https://auctions.stacksbowers.com/l...-gold-shield
Pillar of the Community
United States
2548 Posts
 Posted 07/28/2021  10:04 pm  Show Profile   Bookmark this reply Add Oldfordman to your friends list Get a Link to this Reply
Most likely from the fingers of a person. The high points is where it gets caught easier. Or it could be dirt from a cleaning.
Bedrock of the Community
Australia
18997 Posts
 Posted 07/28/2021  10:35 pm  Show Profile   Bookmark this reply Add sel_69l to your friends list Get a Link to this Reply
An obvious first step is to give the coin a long soak in acetone, then rinse with distilled water.

If the coin is in a slab, the slab must necessarily be broken to clean the coin.

Although I completed a type set of 17 Australian sovereigns and half sovereigns, which included included an Adelaide Pound Type 11, 9 Sovereigns and 7 Half Sovereigns, none of these were slabbed. Slabbing was entirely unsuited to my method of display and storage of the completed type set.
All of the coins in my Australian type set were washed using soap and water with the skin on my fingers softened and cleaned first, so that I could rub the coins safely. 22 ct gold is much harder than the skin of water/soap softened fingers.

Do not use this method of cleaning for cameo mirror proof gold coins. These sorts of coins normally come encapsulated from the mint, so should never need cleaning anyway.
However,
even gold coins in worn fine condition really gleam, when gently washed with good old soap 'n water.

If the stain still remains on the coin pictured, one should really question if the alloy is correct to 22ct gold specification.
One approach to prevent cleaning is to slab the coin.
I personally wonder why, if it was slabbed in the first place, that the stains were not removed beforehand.
Valued Member
United Kingdom
75 Posts
 Posted 07/29/2021  03:40 am  Show Profile   Bookmark this reply Add JohnConduitt to your friends list Get a Link to this Reply
It might be wear rather than grime. In certain light, contact marks show up as dark patches on gold. It happens to silver too to a lesser extent, but the colour contrast isn't so obvious. Cleaning wouldn't help at all in that case.
Edited by JohnConduitt
07/29/2021 04:27 am
Pillar of the Community
Learn More...
Canada
4002 Posts
 Posted 07/29/2021  08:33 am  Show Profile   Check Pacificoin's eBay Listings Bookmark this reply Add Pacificoin to your friends list Get a Link to this Reply
The proper term that would be used is
" original skin " in that the coins referrred to above had never been
Dipped or cleaned .
New Member
Germany
39 Posts
 Posted 07/29/2021  08:43 am  Show Profile   Bookmark this reply Add stgaudens to your friends list Get a Link to this Reply
@JohnConduitt: It is definitely not just wear because other worn gold coins don't look like that
@Oldfordman: but why does it appear that often on sovereigns but not that often on other types of gold coins? Did people in the british empire have the dirtiest hands? XD
@sel_69l: I have tried cleaning some circulated coins with soapy water but I think the resulting gleam looks unnatural...

One guess from me: maybe the grime originates from some kind of bad storage? But maybe we have a sovereign expert in this forum who knows more...
Valued Member
United Kingdom
152 Posts
 Posted 08/09/2021  2:47 pm  Show Profile   Check numismatic biz's eBay Listings Bookmark this reply Add numismatic biz to your friends list Get a Link to this Reply
RE dirt quite common on Shield Sovs due to the tin silver zinc copper mix
sovs at that time were often weighted on brass scales thus rubbing on high points and brass left on coins leading over time toning stain on high points.

gold is always mixed with zinc copper tin and silver leading different colours of gold, pre 1900 sovs have slightly different colour than modern ones
Michael @ WorldWideCoins
www.numismatic.biz
Pillar of the Community
Canada
4236 Posts
 Posted 08/09/2021  3:30 pm  Show Profile   Bookmark this reply Add oriole to your friends list Get a Link to this Reply
I am not sure that this is relevent, but I find that circulated Aluminum coins develop a similar looking layer of grime, which seems to come off with soap and water.
Bedrock of the Community
Australia
18997 Posts
 Posted 08/09/2021  8:28 pm  Show Profile   Bookmark this reply Add sel_69l to your friends list Get a Link to this Reply
As I understand it 22ct gold sovs were alloyed with refined copper.
Thus, any trace element that is not gold or copper would be at an extremely low level.

22ct gold coins with copper alloy are nevertheless very capable of toning over a period of many decades, if left undisturbed. There are many examples of this phenomenon that can be found on uncirculated examples, especially of British Guinea coins in the British Museum.

There are two exceptions to this that I am aware of. Both relate to issues from the Sydney Mint.
Arsenic was found in some sovereigns that were tested by The Royal Mint in London, because some of them were found to be brittle, and the presence of a trace amount of arsenic was found to cause the brittleness.

All Sydney Mint sovereigns and half sovereigns from 1855 until 1866 were alloyed with silver, and not copper. These coins have a richer, but slightly paler golden color, that is seen in all grades.
The Royal Mint in London objected to this alloy, and so it was changed to standard copper alloy after 1866.
Pillar of the Community
Australia
1836 Posts
 Posted 08/13/2021  07:12 am  Show Profile   Bookmark this reply Add Mr T to your friends list Get a Link to this Reply

Quote:
RE dirt quite common on Shield Sovs due to the tin silver zinc copper mix


How much tin, silver and zinc? Early Australian sovereigns had silver in them but that was stopped by 1871.
  Previous TopicReplies: 9 / Views: 525Next Topic  
 
To participate in the forum you must log in or register.





Disclaimer: While a tremendous amount of effort goes into ensuring the accuracy of the information contained in this site, Coin Community assumes no liability for errors. Copyright 2005 - 2021 Coin Community Family- all rights reserved worldwide. Use of any images or content on this website without prior written permission of Coin Community or the original lender is strictly prohibited.
Contact Us  |  Advertise Here  |  Privacy Policy / Terms of Use

Coin Community Forum © 2005 - 2021 Coin Community Forums
It took 0.29 seconds to rattle this change. Powered By: Snitz Forums 2000 Version 3.4.05