Mr. Alan Rigby
Trading Standards Department
55 Guildhall Street
Preston
Lancashire
PR1 3NU

Dear Alan

Confirming the oral report I gave you today, I have examined a 7 stone round diamond cluster ring, which I understand was purchased from a Preston jewellery retailer, and believed by the purchaser to be incorrectly described; and I have noted the following:

Weight
To determine the weight precisely, the stones would need to be removed and weighed on a carat balance. A reasonably accurate estimate can be made by measuring the physical dimensions followed by a calculation. This however requires that we can measure the depth of the stones, but due to the design of this ring, it has not been possible except for the centre stone.
The centre stone measures 3.8mm diameter and 2.2mm deep, and I estimate its weight at 0.195 carats. The six outer stones vary in diameter from about 3.0 to 3.2mm, and I can estimate their total weight as being between 0.66 and 0.84 carats, which would give a total weight of between 0.85 and 1.04 carats.
I understand that the ring was described as containing one carat of diamonds, which is within the range of my estimates. On that basis alone I would not believe the one carat description to be inaccurate. There is however some strong circumstantial evidence, namely a mark stamped on the inside of the ring shank reading " . 9 4 ". It is common practice for many manufacturers to stamp either the actual diamond content or the guaranteed minimum content in the shank in this manner. It is highly probable therefore that the diamond content would prove to be only 0.94 carats. This figure is entirely consistent with our measurements, being close to our mid point figure.
Any ethical jeweller would agree that 0.94 carats is not acceptably close to be described as 1 carat; even approximately 1 carat might be considered a slight stretch. To be acceptable as an accurate description, the weight should be a minimum of 0.995 carats, and some would argue for 0.999 carats. On a second-hand piece, when the trader would not be expected to have access to exact data from the supplier the description "approximately one carat" would be acceptable, if it were not for the shank marking, which means "approximately 0.94 carats" would be more appropriate.

Colour
To ascertain precise diamond colour requires the stones to be removed from the mount, and thoroughly cleaned, however it is possible to make a reasonably accurate estimate without removing them.
I believe that the diamonds were described as E to F colour. This is misleading. The centre stone displays quite noticeable colour even to the inexpert eye, and my opinion is that it is approximately J colour. The outer stones are better, and I would estimate them as G to H colour. From the printed information sheets I gave you, you will see that at the very high colour grades there exist only slight actual differences. In particular, I state that the four top grades are almost undetectably close when mounted. It is therefore just possible that the outer stones are accurately described. On balance, it is my opinion that they fail to qualify as E to F colour.

Clarity
To ascertain precise diamond clarity requires the stones to be removed from the mount, and thoroughly cleaned, however it is possible to make a reasonably accurate estimate without removing them. I believe that they were described as VVS1 to VVS2 clarity, and again can state with absolute certainty that they fail to match this description. The centre stone I estimate at SI3 to P1 clarity. This is so far from the described clarity that even a untrained eye could discern the difference. Again the outer stones are better, but even these fail to match their description. I estimate their clarity grades to be between VS1 and SI1. The clarity chart which I gave you will explain the differences.

Valuation
Although I presume that the valuation of the item is not under dispute, I have done a quick reckoning of the comparative values as if for a retail insurance replacement value. As described, the ring would be fairly valued at £2000, although we would probably shade this to, say, £1975. As actually appraised, I would value the piece at £1350. If the ring had to be supplied with Gem Laboratory certification for the stones, this would add considerably to the price, but this would only really be sensible with the higher grade stones. My purpose in providing this valuation is to give you an objective view as to how greatly the optimistic description overvalues the ring.

General
It is surprising in a ring of this purported quality for the centre stone to mismatch the outer stones by such a large degree. Even if the claimed quality were lower, the centre stone would still be a noticeable mismatch to the naked eye of a reasonably discerning consumer. It should be obvious to anybody with any basic training in the jewellery distribution industry.

It is customary to examine diamonds using a colour corrected hand-held magnifying glass of 10 (ten) times magnification. It is the standard piece of equipment for diamond dealers world-wide. Most jewellers possess them. It is unnecessary to use anything of higher power for normal grading, while anything less is irrelevant. Most retail jewellers should possess one. Most retail jewellers rely on their suppliers for the accuracy of the description and the specification of their products. Multiple jewellers have the resources to carry out random checks on their supplies, and most of them presumably do so. Independent retailers do not have such great resources, and it is therefore reasonable of them to place more reliance on their suppliers. It may therefore be relevant to ask the trader in this case if they were supplied with any information by their supplier. The sponsor's mark in the ring appears to be HWT, which at a guess belongs to H. W. Tankel of Glasgow. If they have misdescribed the piece then they should at least be advised about the need for more care. If they have not given the retailer a detailed description, then it could be assumed that the retailer claims his own expertise on which to base his descriptions. In either case, it clearly is the traders responsibility to take reasonable care to verify the accuracy of his claims. It would certainly be good practice for the retailer to note down on the receipt or a valuation his confirmation of any relevant information which he may have given the customer orally during the sale. It may be worth retrospectively asking the retailer to provide such a valuation, reminding him of the oral description which was given at the time of purchase.

Whilst I am happy to provide this expert opinion and report, and would be perfectly prepared to confirm all the above under oath, in the event that you were to prosecute the trader, and wanted an expert witness of impeccable authority, then my recommendation would be to use the London Gem Lab, whose address you have.

I am happy for you to show this report to either or any other party, together with any other supporting material. If you wished me to attend court as an expert witness, then I would expect to agree a fee with you, otherwise I am only too happy to give you preliminary help and advice on this or any other occasion in the future. I am often asked by members of the public for opinions and advice about jewellery, and try to give such advice freely and fairly regardless of the identity of any other traders involved.

As you mentioned, the low level of complaints about jewellery are probably because of the public's limited knowledge about jewellery rather than because of the accuracy and honesty of the jewellery distributive industry. It is part of my goal to help to educate the public about jewellery, partly because I believe that an educated consumer would be more likely to be a "Chard" customer, and partly because I dislike the poor quality goods and advice that most of the public now gets.

I trust you will let me know the outcome of this case in due course, and please do not hesitate to use us for any advice in the future.