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Thread: 9ct Rose gold tested as Copper

  1. #1
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    Default 9ct Rose gold tested as Copper

    Hi Everyone,

    I'm hoping someone can help me with the predicament I have found myself in. I recently created a ring in 9ct rose gold, the band was thin and fell below the hallmarking Requirement so I did not feel the need to get it done. The customer who purchased the ring ordered the wrong size so took the ring to their local jewellers for resizing.

    The jewellers looked at the ring and saw no hallmarking so automatically claimed it was copper. The customer naturally being distraught contacted me to tell me of the claim. I was shocked I purchased the wire from cooksongold so had nothing to worry about and asked the customer to get the ring tested. So the customer got the ring tested and to my absolute surprise the company who is a reputable company established for a very long time wrote a formal letter saying the ring did In fact test as copper.

    I honestly can not believe this. Like I said I have only ever purchased my wire from cooksongold, I even have proof of purchase from cooksongold.

    I have asked the customer to send the ring back so that I can get it tested but I want to know can 9ct red gold test as copper?

  2. #2
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    9ct is 9ct, that is 375 gold and that's what it should test as. Get it back and send it to the assay office for hallmarking. Whether accepted, or rejected, you can act accordingly. Dennis.
    Last edited by Dennis; 18-01-2019 at 03:57 PM.

  3. #3
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    Quote Originally Posted by cartres View Post
    can 9ct red gold test as copper?
    No, absolutely not. I know this because I have recently started working with 375 Rose gold and I had to be sure my alloy mix was right. I sent a sample of 375 Rose gold to the London Assay Office to have a complete compositional analysis and they measure down to parts per thousand using XRF (X-ray fluorescence spectrometry).

    See this link:http://www.assayofficelondon.co.uk/o...atory-services

  4. #4
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    If I was working in 9ct red gold, which I don't, I'd be having it hallmarked, whether it was below the weight or not, as its gold and has a perceived higher value. That then takes the confusion out of the equation with customers.
    Jules

  5. #5
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    I got the ring back from the customer today and decided to take it to my local jewellers and they tested the ring and came back and said it is without a doubt 100% gold. I returned home and called up the company who tested initially and they were adamant it was definitely copper even though I purchased the wire from cooksongold and had it tested myself and it is gold. The jewellers who got it tested the first time is very reputable as is the jewellerys who tested it the second time. I am even more confused as to why the difference of opinion. Can a test be incorrect?

    Needless to say I won't be sending any gold items without hallmarking even if it is below the hallmarking Requirement because it isn't worth the hassle.

  6. #6
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    Thank you for coming back to us. As you say, the local jeweller shops have confused the matter further. The assay office is the ultimate authority.
    BTW, a 9carat ring is only 37.5% gold. Dennis

  7. #7
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    Quote Originally Posted by cartres View Post
    I got the ring back from the customer today and decided to take it to my local jewellers and they tested the ring and came back and said it is without a doubt 100% gold. I returned home and called up the company who tested initially and they were adamant it was definitely copper even though I purchased the wire from cooksongold and had it tested myself and it is gold. The jewellers who got it tested the first time is very reputable as is the jewellerys who tested it the second time. I am even more confused as to why the difference of opinion. Can a test be incorrect?

    Needless to say I won't be sending any gold items without hallmarking even if it is below the hallmarking Requirement because it isn't worth the hassle.
    I don’t know what method jewellers use to test the purity of metals, but as I said earlier, I have had metal tested at the London Assay Office and they measure down to parts per thousand. This means they could measure as little as 1g of gold in a 1kg alloy mix!

    The reason I like to use the LAO is they don’t interpret the result, they just give you the figures and it’s up to you to understand whether it means it is 9ct, 14ct etc.
    Rose gold is almost 60% copper, so one jeweller might interpret that as being copper if they are expecting 18ct gold, I doubt that’s the case but it could explain the discrepancy.

  8. #8
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    The reliability of the test involved depends on a number of factors.

    In order of reliability, I'd go for:
    Cupellation & formal assay - requires quite a lot of kit and lab-grade training
    XRF analysis - expensive kit, not much training but can be mucked up by some plating
    Touchstone & acid - needs training to use it and looks for a direct comparison of the action of acid on 1 known & 1 unknown sample. Surprisingly accurate wrt the samples used.
    More modern acid kits (which don't need a touchstone) are much the same. Not quite as accurate as they don't have samples to compare against.
    Electronic testers - susceptible to user error, inadequate cleaning, dodgy contact... OK for low-carat golds as a quick & dirty check.

    https://www.quicktest.co.uk/acatalog/Gold_Testers.html has more info on most of them.

  9. #9
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    Unless I'm mistaken, the most accurate method of testing--Cupellation--is a destructive test so it's not something you would want to perform on a finished piece of jewellery. Since the OP bought the wire from Cookson I would say the onus is on them to verify the purity in a dispute. (I'm not an expert in Law but I did a lot of research on product liability before selling anything)

    In any dispute, such as the OP has experienced, the final retailer would require to show due diligence. For me, because I make my own alloy mix, I send a sample to the LAO to have it tested using the most accurate method possible, regardless of whether it is destructive or not. I then have a record as evidence of my due diligence.

    Of course the solution would be to have everything hallmarked after it is made, but I think that unnecessarily increases time and cost of getting the final item to market.

  10. #10
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    Quote Originally Posted by handmadeblanks View Post
    Unless I'm mistaken, the most accurate method of testing--Cupellation--is a destructive test so it's not something you would want to perform on a finished piece of jewellery.
    While that's true, you don't generally have the entire piece tested that way... That would be rather silly. When it is done - and none of the pieces I've submitted over the past 15 (ish?) years have been subjected to this - a small sample is removed from an inconspicuous area (or so we hope) and the assay is done on that sample. The refined sample is then returned along with the hallmarked object.

    In a similar vein, it used to be that objects failing hallmarking were destroyed; now they're invariably (wriggle room for the occasional exception) returned.

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