After spending months searching Pricescope and doing rather comprehensive internet research, I have decided to put something back into the forum and write my only little 'FAQ' to summarise what I have learnt.
Basics of Diamond Purchasing - The Four C's
In order of importance:
Cut - This is by far the most important aspect of the Four C's. It is often given less importance by many B&M (brick and mortar - i.e. your average shopfront jewellers). They do this because their stones may not be 'ideal cut' or of a 'more average quality' and there is a general market perception amongst consumers (and ladies) that value carat and clarity over the quality of the cut. The other reason is that mentioning the 'cut grade' has only been marketed and included on grading certificates in recent years, with GIA only beginning to issue cut grades in early 2006.
The Cut is what defines the diamond's brilliance, sparkle and scintillation. Above all else, it determines the diamond's beauty. Diamond cutters are beginning to take advantage by 'branding' ideal cut diamonds and then charging (of course) a price premium for them.
An ideal cut diamond of a lower colour, clarity and size may look larger (because of better edge-to-edge light return or less edge leakage) and more visually appealing than a D/IF 'average' or only 'good/verry good' diamond.
Some vendors will lead you to believe cut only defines the shape. To some extent, cut also refers to whether the stone is a round brilliant, princess, emerald etc... but it means so much more than that.
Grading cut:
A topic of much controversy and discussion
The quality of a cut is better researched in a round brilliant diamond. However, there are two different methods of grading cut.
1. Judging the Proportions - over the years, many mathematicians have studied the ideal proportions of a diamond, the benchmark being the Tolkowsky standard. Search HCA / GIA facetware / AGS cut tables etc... for what are considered 'ideal proportions'.
2. Judging visual performance of a stone in terms of brilliance, fire, scintillation and spread. This is what Garry Holloway has pioneered in his HCA. And also the new AGS grades - there are within the 'ranges in a table of ideal proportions' an infinite number of combinations, some that may not be ideal. The only way to tell how good a diamond is - of course - is to look at it, and these are what the new cutting grades are based upon.
Symmetry and Polish are also important in the quality of the cut. However, a 'very good' may be as acceptable as 'excellent' and it plays a lesser role than the relationship between the proportions of the diamond.
Hearts and Arrows refer to a diamond with exceptional symmetry - not necessarily quality of the cut - and proportions that results in perfect arrows table up and hearts when viewed from below (from the pavillion) using a H&A viewer. Some H&A diamonds look worse than non H&A diamonds and vice versa.
For assessing 'cut' I would refer you to the HCA, the idealscope, ASET and of course, the cut grading on an AGS or GIA certificate. Neither are perfect in itself, but used in combination are tools that allow you to eliminate poor performing diamonds. The best judge of a diamond is yourself. This cannot be emphasized. Even within a perfect 'ideal, AGS 000 stone' there are combinations that emphasize brilliance or fire or another particular attribute over another that may be preferential to one person but not the other. This is splitting hairs - generally an AGS 000 'a cut above' stone would satisfy many people and look gorgeous!!!
There are countless discussions as to different proportions (e.g. shallow stones vs deep stones vs ideal stones) that would be be far beyond my understanding and depth of this post. Also note that not all cut information is included on most certificates - they are often rounded average figures and only a full analysis e.g. Sarin or Helium will tell you how 'tightly' cut the stone is.
You need to have an idea of what an ideal stone and what I am talking about. That means seeing ideal-cuts and having seen examples before purchasing. As this may not be available if you buy online, I refer you to the videos on Rhino's website at www.goodoldgold.com , information on www.idealscope.com for IS reference charts and of course, browse the 'a cut above' diamonds on whiteflash or signature diamonds of other vendors to see what they look like.
A girdle on a round brilliant should be somewhere between thin to slightly thick.
Painting/digging/enhancements are a topic for another day.
Carat:
The rest of the 4 C's are more straightforward.
1Ct = 0.2 grams. There are magical marks where the price takes a significant hike. 0.90 Ct costs at least 25% less than 1.10 Ct per carat. So if the magical 'one' number doesn't mean much, you'll save money going slightly less.
Also, carat = weight. Not size. A formula for calculating roughly the diameter of a round brilliant is cube-root of the Carat Weight x 6.5mm (6.5mm being the standard diameter of a 1Ct stone).
Poor cuts exist as carat weight = money more so than cut!!! Yet cut is more important in making sure you're not paying for dead-weight or a poorly cut stone.
Spread as Garry Holloway puts it is 'desirability' and refers to how a diamond of a specific Ct weight compares to the diameter of a benchmark ideal cut. For instance, a 0.70 Ct that has the diameter of a 0.75 Ct stone has 'good spread' as in a ring, it appears larger (provided it is also well cut). Highly spread stones are often more shallow.
Clarity:
An IF stone costs a lot more than a VVS stone. And a VS is a LOT cheaper. As a rule of thumb - there is no difference without a loupe (e.g. looking purely with the eye) visually between a VS stone and an IF stone. So clarity is a good way to save money.
Higher clarity stones may be structurally more sound (e.g. less prone to damage ... for instance during tension settings).
Asian markets prefer the perfect IF. Most people on a budget see no difference and save money on a VS.
An SI is more challenging as sometimes they can influence the stone in a negative way optically.
Eye-clean is an important term in that it means that inclusions are not visible under the naked eye. Which means it looks like a flawless without a loupe.
Colour:
I can tell the difference between a D and a F. You may not.
Colour is judged by flipping a stone table-down and comparing the colour on a white background to that of a set of master stones. Many people save money by going 'slightly yellow' - e.g. G,H,I as once the stone is set 'table up' it is often very difficult to discern the colour and often, especially in a well cut stone (there we go again about the importance of cut) - people will notice the diamond's overall beauty before the colour. (unless you have a fancy pink)
The flawless white colours are lovely. But the difference once set is often insignificant ... Most asians and perfectionists prefer a white (D-F) whereas a lot of people and B&M stores have stones that are of lower colour grades.
There is more of a difference in price between a D and E than an E to F.
How do I know the 4 C's of my diamond?
A proper grading certificate from a reputable laboratory (some labs are 'looser' in their gradings, which mean they give better gradings whch result in a higher price for a diamond than they actually are). AGS is the preferred laboratory on Pricescope, although GIA and many others are acceptable. Tiffany for example use their own laboratories.
A Sarin or analysis of the proportions of your diamond to confirm that the certificate is accurate.
An appraisal an often include the above analysis and also walk you through why your diamond is priced the way it is ... or how much your diamond is 'really' worth. Be wary of the valuer who over-inflates the value to improve his comission or the jewellery store profit.
Preferably buy a diamond either from a reputable source or with a laser inscription you can 'read' so you - yourself - can confirm that the stone you are purchasing is the one mentioned on the pieces of paper that come with it. You need a loupe for this.
Also important is to have a rough idea how much a diamond of the colour, cut, clarity and carat you want should sell for... post on PS if you're uncertain. There's no point knowing the 4 C's and getting then all right ... then paying twice what you should for it!
Reputable internet vendors often mentioned on PriceScope:
Not by any means a comprehensive list so apologies to those missed.
However, www.whiteflash.com and www.goodoldgold.com are often mentioned. As are Blue Nile and many other vendors such as Winfields.
Look up the vendor's reputation on PriceScope and also their returns policy before you buy.
Whiteflash offer a PS discount for example and have comprehensive stone information (IdealScope, Sarin etc...).
In Australia, Garry Holloway's "Precious Metals" (despite the fact I feel his site could do with a redesign to be more attractive ... just look at the Tiffany or Cartier websites!!!) is probably the vendor of choice for loose diamonds.
A diamond shop should educate you about diamonds and make it a plesant learning experience ... not push a sale like a car yard's salesman. An educated buyer is an informed buyer is a smart buyer. Know your stuff (or just post on PS)
Engagement Ring Settings:
If you want an exact branded setting (e.g. exact Tiffany) buy from their store. It is illegal and unethical to exactly copy a setting.
However, there are many similar 'imitation' settings available ... after all, Tiffany can't trademark all 6-prong knife-edge settings can they?
For a round brilliant, there are 4 prong settings, 6 prong settings, high/low settings, tension settings, bezel settings... the list goes on. Just look at the branded websites or whiteflash or any other jeweller, pick one you like - then pick a designer (or go with the one you like) and say 'that's what I want'.
Metals for the ring itself - a discussion can be found in the FAQ titled: https://www.pricescope.com/community/threads/common-alloys-used-in-jewelry.55281/ Common Alloys in Jewellery.
And GET YOUR RING SIZES RIGHT BEFORE YOU ORDER.
Note ring sizes go up 1/4 to 1/2 size in Summer as your fingers swell.
Speaking of which, take your rings off if you get pregnant ... you may regret it later on when your fingers really swell and somebody has to cut either the ring or your finger off ... *muahahahahaha!!!*
There are many good FAQ's and education resources out there:
Pricescope Forums / FAQ
Information resources on the websites of many of the active contributers in this forum - some of which have jewellery stores and websites which also have an abundance of information.
I will edit this post as I find time ... and perhaps add to it.
Basics of Diamond Purchasing - The Four C's
In order of importance:
Cut - This is by far the most important aspect of the Four C's. It is often given less importance by many B&M (brick and mortar - i.e. your average shopfront jewellers). They do this because their stones may not be 'ideal cut' or of a 'more average quality' and there is a general market perception amongst consumers (and ladies) that value carat and clarity over the quality of the cut. The other reason is that mentioning the 'cut grade' has only been marketed and included on grading certificates in recent years, with GIA only beginning to issue cut grades in early 2006.
The Cut is what defines the diamond's brilliance, sparkle and scintillation. Above all else, it determines the diamond's beauty. Diamond cutters are beginning to take advantage by 'branding' ideal cut diamonds and then charging (of course) a price premium for them.
An ideal cut diamond of a lower colour, clarity and size may look larger (because of better edge-to-edge light return or less edge leakage) and more visually appealing than a D/IF 'average' or only 'good/verry good' diamond.
Some vendors will lead you to believe cut only defines the shape. To some extent, cut also refers to whether the stone is a round brilliant, princess, emerald etc... but it means so much more than that.
Grading cut:
A topic of much controversy and discussion
The quality of a cut is better researched in a round brilliant diamond. However, there are two different methods of grading cut.
1. Judging the Proportions - over the years, many mathematicians have studied the ideal proportions of a diamond, the benchmark being the Tolkowsky standard. Search HCA / GIA facetware / AGS cut tables etc... for what are considered 'ideal proportions'.
2. Judging visual performance of a stone in terms of brilliance, fire, scintillation and spread. This is what Garry Holloway has pioneered in his HCA. And also the new AGS grades - there are within the 'ranges in a table of ideal proportions' an infinite number of combinations, some that may not be ideal. The only way to tell how good a diamond is - of course - is to look at it, and these are what the new cutting grades are based upon.
Symmetry and Polish are also important in the quality of the cut. However, a 'very good' may be as acceptable as 'excellent' and it plays a lesser role than the relationship between the proportions of the diamond.
Hearts and Arrows refer to a diamond with exceptional symmetry - not necessarily quality of the cut - and proportions that results in perfect arrows table up and hearts when viewed from below (from the pavillion) using a H&A viewer. Some H&A diamonds look worse than non H&A diamonds and vice versa.
For assessing 'cut' I would refer you to the HCA, the idealscope, ASET and of course, the cut grading on an AGS or GIA certificate. Neither are perfect in itself, but used in combination are tools that allow you to eliminate poor performing diamonds. The best judge of a diamond is yourself. This cannot be emphasized. Even within a perfect 'ideal, AGS 000 stone' there are combinations that emphasize brilliance or fire or another particular attribute over another that may be preferential to one person but not the other. This is splitting hairs - generally an AGS 000 'a cut above' stone would satisfy many people and look gorgeous!!!
There are countless discussions as to different proportions (e.g. shallow stones vs deep stones vs ideal stones) that would be be far beyond my understanding and depth of this post. Also note that not all cut information is included on most certificates - they are often rounded average figures and only a full analysis e.g. Sarin or Helium will tell you how 'tightly' cut the stone is.
You need to have an idea of what an ideal stone and what I am talking about. That means seeing ideal-cuts and having seen examples before purchasing. As this may not be available if you buy online, I refer you to the videos on Rhino's website at www.goodoldgold.com , information on www.idealscope.com for IS reference charts and of course, browse the 'a cut above' diamonds on whiteflash or signature diamonds of other vendors to see what they look like.
A girdle on a round brilliant should be somewhere between thin to slightly thick.
Painting/digging/enhancements are a topic for another day.
Carat:
The rest of the 4 C's are more straightforward.
1Ct = 0.2 grams. There are magical marks where the price takes a significant hike. 0.90 Ct costs at least 25% less than 1.10 Ct per carat. So if the magical 'one' number doesn't mean much, you'll save money going slightly less.
Also, carat = weight. Not size. A formula for calculating roughly the diameter of a round brilliant is cube-root of the Carat Weight x 6.5mm (6.5mm being the standard diameter of a 1Ct stone).
Poor cuts exist as carat weight = money more so than cut!!! Yet cut is more important in making sure you're not paying for dead-weight or a poorly cut stone.
Spread as Garry Holloway puts it is 'desirability' and refers to how a diamond of a specific Ct weight compares to the diameter of a benchmark ideal cut. For instance, a 0.70 Ct that has the diameter of a 0.75 Ct stone has 'good spread' as in a ring, it appears larger (provided it is also well cut). Highly spread stones are often more shallow.
Clarity:
An IF stone costs a lot more than a VVS stone. And a VS is a LOT cheaper. As a rule of thumb - there is no difference without a loupe (e.g. looking purely with the eye) visually between a VS stone and an IF stone. So clarity is a good way to save money.
Higher clarity stones may be structurally more sound (e.g. less prone to damage ... for instance during tension settings).
Asian markets prefer the perfect IF. Most people on a budget see no difference and save money on a VS.
An SI is more challenging as sometimes they can influence the stone in a negative way optically.
Eye-clean is an important term in that it means that inclusions are not visible under the naked eye. Which means it looks like a flawless without a loupe.
Colour:
I can tell the difference between a D and a F. You may not.
Colour is judged by flipping a stone table-down and comparing the colour on a white background to that of a set of master stones. Many people save money by going 'slightly yellow' - e.g. G,H,I as once the stone is set 'table up' it is often very difficult to discern the colour and often, especially in a well cut stone (there we go again about the importance of cut) - people will notice the diamond's overall beauty before the colour. (unless you have a fancy pink)
The flawless white colours are lovely. But the difference once set is often insignificant ... Most asians and perfectionists prefer a white (D-F) whereas a lot of people and B&M stores have stones that are of lower colour grades.
There is more of a difference in price between a D and E than an E to F.
How do I know the 4 C's of my diamond?
A proper grading certificate from a reputable laboratory (some labs are 'looser' in their gradings, which mean they give better gradings whch result in a higher price for a diamond than they actually are). AGS is the preferred laboratory on Pricescope, although GIA and many others are acceptable. Tiffany for example use their own laboratories.
A Sarin or analysis of the proportions of your diamond to confirm that the certificate is accurate.
An appraisal an often include the above analysis and also walk you through why your diamond is priced the way it is ... or how much your diamond is 'really' worth. Be wary of the valuer who over-inflates the value to improve his comission or the jewellery store profit.
Preferably buy a diamond either from a reputable source or with a laser inscription you can 'read' so you - yourself - can confirm that the stone you are purchasing is the one mentioned on the pieces of paper that come with it. You need a loupe for this.
Also important is to have a rough idea how much a diamond of the colour, cut, clarity and carat you want should sell for... post on PS if you're uncertain. There's no point knowing the 4 C's and getting then all right ... then paying twice what you should for it!
Reputable internet vendors often mentioned on PriceScope:
Not by any means a comprehensive list so apologies to those missed.
However, www.whiteflash.com and www.goodoldgold.com are often mentioned. As are Blue Nile and many other vendors such as Winfields.
Look up the vendor's reputation on PriceScope and also their returns policy before you buy.
Whiteflash offer a PS discount for example and have comprehensive stone information (IdealScope, Sarin etc...).
In Australia, Garry Holloway's "Precious Metals" (despite the fact I feel his site could do with a redesign to be more attractive ... just look at the Tiffany or Cartier websites!!!) is probably the vendor of choice for loose diamonds.
A diamond shop should educate you about diamonds and make it a plesant learning experience ... not push a sale like a car yard's salesman. An educated buyer is an informed buyer is a smart buyer. Know your stuff (or just post on PS)
Engagement Ring Settings:
If you want an exact branded setting (e.g. exact Tiffany) buy from their store. It is illegal and unethical to exactly copy a setting.
However, there are many similar 'imitation' settings available ... after all, Tiffany can't trademark all 6-prong knife-edge settings can they?
For a round brilliant, there are 4 prong settings, 6 prong settings, high/low settings, tension settings, bezel settings... the list goes on. Just look at the branded websites or whiteflash or any other jeweller, pick one you like - then pick a designer (or go with the one you like) and say 'that's what I want'.
Metals for the ring itself - a discussion can be found in the FAQ titled: https://www.pricescope.com/community/threads/common-alloys-used-in-jewelry.55281/ Common Alloys in Jewellery.
And GET YOUR RING SIZES RIGHT BEFORE YOU ORDER.
Note ring sizes go up 1/4 to 1/2 size in Summer as your fingers swell.
Speaking of which, take your rings off if you get pregnant ... you may regret it later on when your fingers really swell and somebody has to cut either the ring or your finger off ... *muahahahahaha!!!*
There are many good FAQ's and education resources out there:
Pricescope Forums / FAQ
Information resources on the websites of many of the active contributers in this forum - some of which have jewellery stores and websites which also have an abundance of information.
I will edit this post as I find time ... and perhaps add to it.
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