Use access key #2 to skip to page content.

How To Properly Buy A Diamond



March 04, 2010 – Comments (14)

This post is in direct response to an erroneously bad thesis put forth tonight by a fellow caps blogger suggesting an eight year old article holds precedence over diamond buyers today and that buying online is your best course of action. Rather than allowing my ideas to get lost in the comment section of blogs, I'd much rather post my first blog of March and allow the viewing public and my faithful readership to be able to see the other side of the issue. This is not my first post regarding the diamond industry and I'm sure it will not be my last. 

I'm going to go right ahead and proclaim myself "possibly" the most knowledgable person on this site when it comes to diamonds and what to look for in them ( I also have GIA and AGS accreditations to back up that claim).

So much has been said here that was just plain hard to read or downright wrong that it was difficult...but I mustered on and finished. Now that I've read this "piece"...allow me to entertain you with the various facets of what makes a diamond worth what it's worth and this time I won't cut any corners (no pun intended) and paraphrase. 

A diamond is worth what it's worth due to a combination of four factors which were touched on above: carat weight, color, clarity and cut.

Carat Weight is very simply how much your diamond weighs. As alluded above there are such things known in the industry as magic numbers whereby the price jumps drastically just to get an extra smidgen of weight. Think of it like this... there are 100 pennies to a dollar. There are also 100 points to a carat. If you have a 45 point diamond, you cannot legally call that a half carat diamond, so sayeth the Government. But a 46 point diamond CAN legally be called a half carat diamond and thus it's price could vary dramatically from a diamond just one point below. I hear often how customers want a diamond cut to a weight just below a magic number but often these are considerably tougher to find. Although a cutter desires to make the most beautiful diamond imaginable, he also needs to put money in his pocket and food on his table. Often this means that he/she needs to cut a diamond to a level where it achieves a magic number and not a level just below it. This isn't always the case, but often is true.

Color is the second factor we mentioned and is merely a determinant of how much underlying yellow (or other color) the diamond shows when graded loose in daylight equivalent light. Most diamonds contain nitrogen and that is the main cause for the yellow color you may see. Color is graded just like the alphabet minus the letters A, B & C. The reason for this is back in the early 1930s a system was in place that used these letters with pluses or minuses to grade color and GIA wanted to start fresh, thus the beginning letter of D. Color is often graded using a masterstone set and it is true that a one letter difference in color is often invisible to the naked eye of a consumer. D through F represents the colorless scale whereby both a face up (table facing you) and face down (culet facing you) view show no color. This represents less than 5% of all mined diamonds. G through J represents the near-colorless scale whereby a face up examination reveals no color but a face down examination shows slight yellowing in the belly of the pavilion. This is where most of your marketable diamonds will be found in stores. Color has no effect on the quality of the cut, clarity or carat weight but it does have a visually pleasant or unpleasing effect on the viewer.

Clarity is the third factor that helps determine the beauty and rarity of a diamond. Clarity determines exactly what is inside your diamonds such as, whether or not it can be seen with your naked eye or if you need 10x magnfication to see it, how many clarity characteristics there are, where are they located, what color are they and how big they are. The scale goes as follows F-IF-VVS1-VVS2-VS1-VS2-SI1-SI2-I1-I2-I3. One of the biggest differences in price can be found at the I1-SI2 level. Anything at the I1 level and lower can probably be seen by the naked eye while grades higher than SI2 are often invisible to the naked eye. As you increase up the scale beyond SI2, in most cases, you are merely increasing the rarity of that stone. It's effect on sparkle will be helpful but relatively negliable all things told. What needs to be understood about clarity grading though is that it is subjective. One lab to the next may not agree exactly on the grade but you can be assured that AGS and GIA have the two most respected labs in the country. In addition clarity grading is all done based on the size of the stone. A very large stone, say 4 carats or more could be graded a VS2 for example and still have a small eye visible inclusion. Everything is relative to the size of the stone and subjective to the grader.

The final and indeed most important factor in selecting a diamond is the quality of its cut. Cut in itself can effect the price of a diamond well in excess of 50%.... these are numbers straight out of the American Gem Society. A diamond used to be all about the clarity and color but not anymore. It's no longer about what a diamond was, but what a diamond does. Sparkle and that wow factor are indeed what a diamond is all about and it comes from three particular factors: Light performance, Symmetry and finish.

Light performance can indeed be measured and unlike the article above, jewelry stores DO have access to these machines and AGS HAS indeed put out a measuring device to measure light performance.  The Angular Spectrum Evaluation Tool or ASET from AGS can show in four easy colors where the 1) bright light of your diamond enters and exits, where the 2) indirect light from walls etc enters and exits your diamond, where 3) the contrast areas of your diamond are (let's face it, diamonds aren't all white or all black...they need a bit of both to be eye-pleasing) and 4) where areas of light leakage are. How do I know this? Because I use an ASET machine daily. I've also used a Sarin grading machine from time to time. Table percentages, pavilion angles, crown angles and total depth percentage aside, there are 1.3 million ways to create an ideal cut diamond and this machine helps shows each and every diamonds varations and overall performance to light.

Symmetry is another component of cut. As mentioned in the article, symmetry is what is responsible for creating the Hearts & Arrows design that we've all heard about. Those diamonds are indeed a grade 0 for symmetry in that the points of their facets line up properly, but a Hearts and Arrows diamond can also be cut shallow or deep and still show that pattern. It does not really factor in light performance by itself and is just another factor in getting to that perfect light performance. 

Finish is the final factor that comprises cut and describes the polish that is put onto a diamond after the cutting process. Often there are nicks, abrasions or polish lines left after the cutting process and the fashioners ability to remove these marks determines another factor in the cut grade.

A cut grade is only as good as its worst component, so in order to be graded as an AGS Ideal all three components (light performance, symmetry and polish) need to be a 0. The scale if I haven't mentioned it already is rated as 0 to 10 with 0 being Ideal and 10 being poor. So if we saw a grade of 0-2-0, the cut grade is 2. Cut is only as good as the weakest link.

Also while we are on the subject of cut...I'd like to mention a bit about Marcel Tolkowsky. He did indeed develop the ideal cut diamond proportions in a time long before calculators which was indeed a 53% table. Keep in mind though that Tolkowsky's family still produces diamonds to these proportions. Not all ideal cut diamonds can be Tolkowsky's but all Tolkowsky's are ideal cut diamonds. 

And then there's fluorescence which is often forgotten. Although most research hasn't shed too much light as to what causes flourescence you generally just want to avoid a higher level because it can under normal lighting circumstances make the diamond look oily. 

The biggest beef of all with this article other than the lack of knowledge that jewelry stores do indeed have access to this technology and that associates don't know a thing about light performance (because they do otherwise I wouldn't be writing this), is the notion that the best place to buy a diamond is over the internet. 

The absolute worst thing you could do is buy your diamond jewelry over the internet. You could read 1000 lab reports and that still won't make you as much of an expert as physically being in the store and looking at a diamond first hand. There isn't a report in this world that's going to give you the feeling of whether or not she will like that diamond you're picking out unless you are physically in the store and looking at it yourself. You can't get real world results without real world experience and the internet just can't provide that, nor the service that you will need after your purchase. 

I'd also like to point out that attempting to compare prices between diamonds is like trying to pit two gas stations against each other. They are valued appropriately given their cut, color, clarity and weight and your best bet is to go to a non-discount retailer to be assured you are getting a price that is not ridiculously marked up (to then be marked down at various levels throughout the year).

Intenet companies are always going to undercut traditional jewelers just like ebay will always undercut the competition because they are trying to get you take on the risk of buying something from someone you don't know and will never meet. The end result here is just a cat and mouse game of how much lower does the internet crowd need to go to get you to take a risk. It's gambling in purchase form. Some people will choose to pay 3% more to be taken care of for life rather than to form a point and click relationship with someone they've never met from a company that knows them as a statistic. Some people would rather see the product for themselves before buying it. I sure as hell wouldn't drop $50,000 on the car of my dreams without test driving it first (2008 Tungsten Gray Shelby GT 500 in case anyone is in a buying mood) and I don't think any man in their right mind is going to drop a large amount of money on a diamond without seeing it first.

Are you really willing to sacrifice the longevity of your ring to save $100? What's $100 in the long-run of your marriage... 4 dollars a year maybe? Do you think these internet companies even own these diamonds you're looking at online? They're on consignment somewhere and brought in when someone clicks "buy" on the internet. Diamonds are about love and marriage and the internet diamond experience is about as far from that as you can get.

I have spoken....


On a side note... Ask A Blunt Man is still running so keep those comments coming, this is merely a side blog to keep my mind entertained.

14 Comments – Post Your Own

#1) On March 04, 2010 at 11:23 PM, Pennyperson (< 20) wrote:

So, do you give deals to the fellow fools..HA

Report this comment
#2) On March 04, 2010 at 11:31 PM, SockMarket (34.48) wrote:

excellent piece UL. even if I am a bit young to use it. One point: $100 at $4 a week would have you married for 6 months and a week. I would hope that everyone's marriage lasts a little longer than that. If it were over 10 years it would come to $0.19 a week.

Honesly, don't marry anyone you wouldn't spend an extra $0.19 on...

Report this comment
#3) On March 04, 2010 at 11:35 PM, SockMarket (34.48) wrote:

oops. i misread year for week. my bad.

Report this comment
#4) On March 05, 2010 at 12:30 AM, Donnernv (< 20) wrote:

This post doesn't make a lot of sense without reading the original thread.

The real meat is there.

Report this comment
#5) On March 05, 2010 at 12:32 AM, tonylogan1 (27.73) wrote:

sorry, but just to state what I have found to be the obvious...

the best way to buy a diamond is the same way to buy anything...

You need to know a guy.

If you buy a diamond retail, no matter what the discount, you are paying way too much. Take this from a guy who bought from a guy who has a guy.

Report this comment
#6) On March 05, 2010 at 1:04 AM, TMFUltraLong (99.47) wrote:


I did link the original thread but thanks for providing it again


Report this comment
#7) On March 05, 2010 at 2:07 AM, FleaBagger (27.47) wrote:

I thought it was Genndy Tartakovsky.

Report this comment
#8) On March 05, 2010 at 2:19 AM, zzlangerhans (99.80) wrote:

My usual practice is to look for diamonds on the Internet. I then match the diamonds with women I found on the Internet.

Report this comment
#9) On March 05, 2010 at 2:26 AM, TMFUltraLong (99.47) wrote:

My usual practice is to look for diamonds on the Internet. I then match the diamonds with women I found on the Internet.

↑ Best comment yet.....


Report this comment
#10) On March 05, 2010 at 2:52 AM, AndreylikesMTL (96.32) wrote:

Thanks UL

As always, Fun to read.


Report this comment
#11) On March 05, 2010 at 2:13 PM, creek138 (28.57) wrote:

I'd rather buy her a trip around the world and take alot of pictures for the memories. If she cares that much about the worth of a diamond, then she's just a prostitute with a marriage license. Thanks for the inciteful information, but I'm not buying something that will remind me that it (or one like it) was dug out of the ground for $0.50 an hour.

Report this comment
#12) On March 05, 2010 at 5:53 PM, rexlove (99.72) wrote:

I guess I'm one of those fools that did purchase a diamond on the internet. Although overall the experience went well. I bought my wife's engagement ring over the internet. Actually another jeweler later appraised it at about 4 times what I paid for it and it was at least half the price of anything I could get at a jeweler. 

Report this comment
#13) On March 09, 2010 at 9:06 AM, Formula51 (< 20) wrote:


I agree with most everything you said except the statement about buying on the internet.  It sounds like you work at a jewlery retailer and perhaps this is why you feel this way?

I am no gem expert.  It doesnt matter if I look at a diamong 100 times under a microscope, I am not testing for light reflection with the equipment you mentioned, nor do I have the ability to measure/determine cut, symmetry, or polish.  Ultimately, I am taking AGL or GIA's word for it, although seeing it may make me "feel" better. 

With laser inscribed numbers on diamond girdles these days and trusted institues like AGL and GIA, there is NO reason not to buy on the internet in my opinion.  With the caveat being you buy from a respected company like Blue Nile for example.  I can be CERTAIN with a quick trip to my local jeweler that I got the correct diamond and that it matches the certificate I have and if heaven forbid it doesn't, I can send it back and get another one.

I did this (from Blue Nile) and so did my brother just last month.  We both got triple 0 diamonds, G color, VS1, no flourescence, etc. with LASER INSCRIBED numbers certified by GIA.  My stone was 0.64 carrats and was ~$2,000.  That same stone was next to impossible to find locally and would have cost twice as much.  I know this because my local jeweler appraised it as such.

 In my opinion with laser inscribed numbers, GIA or AGL certification, and a quick trip to the local jeweler to verify, there is no reason not to buy online from a trusted company and save THOUSANDS!


Report this comment
#14) On March 10, 2010 at 5:35 PM, Droog74 (65.15) wrote:

So, what is the difference between a diamond dug out of the ground and a man-made diamond, besides the cost, and the approval of the GIA or AGL?

Report this comment

Featured Broker Partners