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Maihem

Density Of Crown Gold

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I've got a 2010 sovereign and a 1982 sovereign and I'm worried about the differences.

The 1982 is significantly more yellow although the 2010 is minted very shiny.

The 1982 looks and feels like it has much more metal. The 1982 is broader, the rim is thinner, the field is thicker (these three check with micrometers), some parts of the relief seem much higher/more substantial.

The 1982 also seems harder (it scratches the 2010 easily but not the other way round, although the shininess might just have changed my perception).

So I'm wondering about trying the Archimedes test with soapy water (to remove the surface tension).

First, should I do this? I'm not interested in numismatics so don't care about affecting the surface quality.

Second, what's the specific density of crown gold or the volume of a sovereign?

Edited by Maihem

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Circulation coins were produced to 1982, and 1983 onwards only collectors proof coins, so it is normal for the later coin to be much shinier. http://www.coins-of-the-uk.co.uk/sov.html

There are a bunch of specs here (but not density), and comments on detecting forgeries

http://en.wikipedia.org/wiki/Sovereign_(British_coin)#Technical_specifications

Technical specifications

Sovereigns minted since 1817 have been produced to a standard specification:[6]

Weight: 7.9881 grams

Thickness: 1.52 mm

Diameter: 22.05 mm

Fineness: 22 carat = 91.67%

Actual Gold Content: 7.3224 grams = 0.2354 troy ounce

NB: Well-worn or used coins may be marginally under manufactured weight[7] and size.

Counterfeiting

To modern eyes the gold sovereign appears quite a small coin, but with a face value of £1 it had, in 1895, the same purchasing power as £150 in 2007. Gold is also a highly dense metal, so a small coin like a sovereign can contain nearly a quarter of an ounce of metal. Another reason for limiting the production of double sovereigns (£2) and quintuple sovereigns (£5) was the relative ease of removing gold from these larger coins — chemically, by filing, or using other techniques; for example, the drilling of small holes into the coin followed by hammering to conceal the holes,[4] or "sweating": shaking a leather bag full of coins for a long period and collecting the gold dust that was knocked off.[8]

Detection of counterfeit coins can be done either visually by comparison with known genuine coins, by using a coin gauge,[9] or by precise weighing and measurement against standard dimensions (see Specifications above).

There are many recorded fake or counterfeit gold sovereigns in circulation,[10] although they are still relatively scarce in comparison to the numbers of genuine coins due to the difficulty of accurately replicating such a small coin economically. With numismatic fakes, the counterfeiter might use the correct proportions of gold, but try to replicate an older coin with special rarity value. Such fakes only present a potential problem to the numismatic collector as they still contain standard bullion content.

Occasionally one comes across fake sovereign coins where the gold is replaced or alloyed with a substitute metal to look like gold. For example, a limited number of fake sovereigns did appear in circulation which were produced with 9ct gold instead of the correct 22 carat composition. Such fakes can be relatively easily detected by measurement and weighing using jewellers scales. Experienced coin dealers will generally detect such fakes immediately as they are obviously underweight or have incorrect size or thickness dimensions. It is more common to come across counterfeit copies of larger gold coins such as the Krugerrand which are easier and more economical to copy.

Gold is, however, a difficult material to counterfeit without detection due to its unique density and colour. Gold is one of the densest metals and therefore much heavier (for equivalent size or volume) than the common metals such as lead, brass, copper and steel that are used to make fake bullion coins. Fake gold coins are either oversize or underweight, or both. A fake made from lead to exactly the same thickness and diameter as a genuine sovereign would be 35% lighter than the genuine coin. If made the correct weight and diameter, it would be 54% too thick.

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http://www.goldsovereigns.co.uk/2007sovereigns.php

Year 2007 Gold Sovereigns

Proof and uncirculated available now for immediate delivery at advance order prices.

The 2007 sovereigns have the familiar St. George and Dragon design, or do they?

St. George and Dragon - Recut Reverse Dies

The traditional St George & Dragon design has been used on sovereigns, with a few breaks, since 1817.

During this long period, there have been a considerable number of minor changes to the dies used for the reverse (tail side). This year, the reverse design appears to have been completely re-engraved, although there was no advance announcement of this from the Royal Mint.

Altered Dies

The first thing we noticed about the 2007 sovereigns was that they were a real pig to photograph.

We try wherever possible to use our own photographs, although sometimes we use images supplied by the various mints, at least on a pre-issue basis, replacing them with our own images as soon as possible after we receive our first deliveries.

Despite our considerable experience in photographing coins, the results can be quite variable. Some coins photograph beautifully, others are really difficult, and require time, patience, and experimentation before we can be happy with the results. The 2007 sovereigns proved to be in the latter category, It took us most of one day to get reasonably acceptable images, and we had to do quite a lot of post-production work on them. It was only once we had the first new images on our websites that we felt we could spare the time to start comparing them, which is when it started to dawn on us that the difference are not all explicable by poor production quality, but that the dies themselves, and also the masters from which they are made, which have been changed.

19th January 2007 - Delivery of Proof Sovereigns Explains Reverse St George and the Dragon Difference!!

Royal Mint Silence

Despite our continued efforts to get official confirmation from the Mint as to why the reverse design of the 2007 sovereign differs so much to the usual reverse design, we have been unable to achieve this; and this includes talking to people who deal with press releases from the Royal Mint!

Certificate Reveals All

We received our first delivery of the 2007 proofs today. On inspecting the certificates, the majority of the pages actually talk about the re-cut dies and how and why they have been used. We can only shake our heads again in bemusement at the fact that between the 4th of January when we received the Uncirculated Sovereigns and today that the numerous people we have spoken to or attempted to speak to at the Mint could not simply confirm this for us!

From St George's Horse's Mouth

The first page of the certificate talks about the neo-classical or Regency style and how Pistrucci was a 'leading exponent' in this when he was designing at the Royal Mint! Without explanation the following page illustrates and we quote, the 'Re-mastered die for the reverse of the 2007 sovereign showing the enhanced detail.'

What is Clear as Day

It seems blindingly obvious that the 2007 sovereign is centred around the re-cut die, and had this been published when the Uncirculated version were released then it would have provoked collectors into wanting to buy what could possibly be a one off change in design. As with the 1989, 2002, and 2005 sovereigns, all of which sell for more than normal years based on their one of designs, the Royal Mint could have capitalised upon this months before by making this announcement. As per usual with the way the Royal Mint can sometimes operate, their failure to announce this only bemuses us!

Chief Engraver Finally Speaks!

Following a biography of Pistrucci, the origin of the 1817 sovereign is then discussed. The final page then explains in detail how they are 'Recapturing Pistrucci's Original Masterpiece.'

What follows is a quote from the Chief Engraver at the Royal Mint, Matthew Bonaccorsi:

'Working in plaster, or on the computer, cannot wholly capture the style of a hand engraved piece. In order to match the look and feel of the original sovereign, therefore, the final work had to be undertaken using the traditional methods'

The Truth, The Whole Truth, and Nothing But The Truth

The certificate then explains what we have speculated on our websites for the past three weeks. For informational purposes, this is the Mint's full explanation of the reverse change for 2007. Reading our original assessment of the new sovereign, our suspicions are more or less completely confirmed!

'For the 2007 Sovereign the Royal Mint is using the latest technology, coupled with traditional engraving skills, to recapture the fineness of Pistrucci's early St. George and the dragon from the period of the Neo-Classical revival during the 19th century.

An original hand-engraved design, modified by Pistrucci himself for the Crown Piece of 1818, was scanned into the computer and a large- scale copy was cut in plaster. Elements of the detail were then worked in by hand to ensure that, as far as possible, a faithful rendering of the design was achieved.

The tooling was produced to the required dimensions of the Sovereign and at this size the engravers again completed the finishing touches by hand.

Through this process the intricate details and contours of the composition have been restored so that the sovereign now stands as a sculptured from in a way that Pistrucci himself would have advised.

The 2007 Sovereigns are indeed a tribute to the great masterpiece. Their owners will be taken back almost two centuries to see Pistrucci's St. George and the dragon sovereigns in all their neo-Classical glory.'

Changes

As far as the obverse is concerned, there appears to be no re-engraving, although there is a considerable loss of definition compared with a year 2000 dated sovereign which we used for comparison. The substantial re-engraving appears to to confined to the reverse side.

Both sides show many signs of hurried, or sub-standard production, with scuffs, radiating striations possibly caused through under-annealing of the blank planchets before striking. Unfortunately Yann, our resident photographer has already cleaned these off our image, to rectify this, we will shortly be creating a separate "Spot the Difference" page.

Almost all parts of the reverse design are different, leading us to conclude that the entire reverse design has been re-engraved. Because of this, it will be almost impossible for us to create a complete catalogue of differences, but we attempt to list the most obvious ones here:-

Lower relief, noticeable or apparent in the centre.

Longer, re-engraved tail.

Longer trailing helmet plumes.

More distinct, possibly cruder, helmet crest.

Completely different folds in cloak.

Smaller right hand, with more defined fingers, gap between sword hilt.

Different mane to horse.

Bigger gap between St George and the horse's neck.

Thinner gap between horse's neck and reins.

Different end to broken lance (to left of ground).

Completely different ground.

Smaller BP initials, rather blurred and indistinct. On our photo, they appear to merge to look like a single letter D.

Dragon's wings differ.

Dragon's nose, mouth, crest, and claws altered.

George's garter is redefined.

Horse's musclature has been substantially changed, as has George's.

The border has been changed, and now looks more like a railway line, as opposed to convex toothed beads. (The obverse border does not match).

The exergue appears to be taller, as do the date numerals.

There is a smaller gap between the border and the main parts of the design.

Obverse

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I've got a 2010 sovereign and a 1982 sovereign and I'm worried about the differences.

The 1982 is significantly more yellow although the 2010 is minted very shiny.

The 1982 looks and feels like it has much more metal.

The 1982 is broader, the rim is thinner, the field is thicker (these three check with micrometers), some parts of the relief seem much higher/more substantial.

The 1982 also seems harder (it scratches the 2010 easily but not the other way round, although the shininess might just have changed my perception).

So I'm wondering about trying the Archimedes test with soapy water (to remove the surface tension).

First, should I do this? I'm not interested in numismatics so don't care about affecting the surface quality.

Second, what's the specific density of crown gold or the volume of a sovereign?

Personally, I've bought all mine from reputable sources and never bothered to even weigh them, much less try the Archimedes test.

I have noticed that circulated coins have a completely different appearance to uncirculated because the copper starts reacting to the fat, moisture etc caused by physical contact. According to one report I've heard, even leaving a new uncirculated coin in the sun for a long time will change its appearance!

Some of my coins have a yellow, pale hue and others (particularly Victorian soversigns) seem to be very prone to red spot hence they look as if they've been stained with tomatoe sauce or something, even after cleaning.

The thickness of the rim does vary. Generally, the harder the coin is stamped by the die the thicker the rim will be. My George IV has a visibly thicker rim than the rest.

Lastly, the quality of the imprint on my new 2009 sovereigns is much worse than my pre decimal QE II and earlier coins - they seem to have manufactured bullion coins to a noticeably better standard in the past. If you want to buy new sovereigns, it might be best to get an order in early (while the dies have been less used and might have sharper edges.)

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Personally, I've bought all mine from reputable sources and never bothered to even weigh them, much less try the Archimedes test.

Thanks folks. Does anybody have a 2010 sovereign and half sovereign. They're a very coppery colour compared to a 2002 uncirculated half-sovereign, and a 1982 circulated full sovereign is almost brassy in comparison and generally more substantial than the 2010 one.

Is this normal and expected variation?

Edited by Maihem

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