There are four main criterions that a diamond is judged by, the Four C's - Carat, Cut, Color, and Clarity. All these combined lend to the value and brilliance of a diamond. Certification of a diamond is a way that one can be absolutely sure they are getting what they want.


Carat weight

     1 Carat is equal to 1/5 of a gram, and is the standard unit used to weigh diamonds. One carat is divided into 100 parts called points: 1ct. = 100 points. Diamond value increases exponentially with size; a 1ct diamond costs more than twice the amount of a 1/2ct of the same quality. This is because crystals large enough to cut a big diamond from are relatively rare whereas the crystals from which ¼ carats are cut are more abundant.

       Certain weights also cost a little more, such as a full 1.00ct as opposed to a 0.91ct or a full 0.75ct as opposed to a 0.66ct. This is just something to consider if you're looking for ways to achieve a certain look while keeping an eye on your budget.



       When we refer to cut, we are referring to the size, arrangement, and precision of the stone's facets and the stone's proportions. For round diamonds, a certain set of dimensions has created which will optimize brilliance and dispersion. In an ideal cut diamond, all light that enters is reflected back out through the top and to your eye. This makes the brightest possible diamond. If the diamond is cut poorly the stone will appear dark, because light is entering the diamond and "leaking" out in directions going away from the viewer's eye. For other fancy shapes and styles, such as the princess cut, the industry has not yet agreed on an ideal set of proportions.

       Ideal cut usually refers to a diamond's table and depth percentages. If a diamond measures just outside the range of ideal proportions, it is premium cut. Why aren't all diamonds ideal cut? Because to cut an ideal diamond from a rough crystal means losing more of the rough crystal than if the diamond is cut to keep as much weight as possible.

       Diamonds are also graded on their symmetry and the precision of their polish. A "triple 0" Ideal has ideal proportions, symmetry and polish. A "hearts and arrows" ideal has these and it displays an optical pattern when looked at through a special scope because it also has an ideal crown angle. There is also a variety of branded diamonds with their own super ideal cuts. You can see that the details of cutting can be precise to a staggering degree. If this intrigues you, we can meet your needs. If this seems overwhelming, don't worry about it. The most important thing is to find a stone that appeals to you.



       People often confuse the effects of color and cut, thinking that the whiter a diamond is, the more it will sparkle. In fact, sparkle is wholly determined by cut.

     Color is the measure of a diamond's body color. Diamonds are made of carbon, so in their purest state they are colorless. Most diamonds have trace elements, such as nitrogen, which impart tints of color, usually yellow or brown. The more color a diamond displays, the lower its value, until it shows enough saturated color to be called "fancy colored". The color grading scale starts at D and progresses through the alphabet to Z. D indicates that a diamond is colorless, with D, E, and F appearing colorless to most people. G, H, I and J are considered near colorless and still appear white. By K, L and M the tinge of color can be seen and below that are shades of light yellow and brown. A diamond beyond Z becomes fancy.



     As diamond crystals grow, much like any crystals, their growth can be interrupted or they can trap other particles or minerals inside themselves as they grow. Practically all diamonds contain some type of internal characteristics. It is the overall impression of the size, nature, number, and placement of these inclusions that determine the diamond's clarity grade. An experienced grader will use 10x magnification when judging clarity.

At the top of the clarity scale are Flawless FL and Internally Flawless IF (internally flawless might have surface scratches)

FL (Flawless) indicates there are absolutely no inclusions in a stone. This type of stone is extremely rare, and is quite expensive for that reason.

IF (Internally flawless) indicates that inclusions only appear on the outside of the stone.

(Very, very slightly included) indicates that the inclusions are minute and extremely difficult to find.

VS1-VS2 (Very slightly included) indicates that the inclusions are minor and somewhat difficult to find.

SI1-SI2 (Slightly included) indicates that the inclusions are relatively easy to find, but only under 10x magnification. We sell many SI stones, but they are not all equal so we're always careful to make sure that the inclusion doesn't run straight to the edge or break the surface of the stone. At that point, the diamond will have an area of weakness.

I1-I3 (Imperfect or included) indicates that the inclusion is visible to the naked eye. At I2, beauty or durability is compromised and at I3, both beauty and durability are compromised.

     Many people are surprised to hear that diamonds can be broken and in fact, it's not so hard to do if the diamond already has internal breaks that reach the surface. A sharp impact at a fragile point is all it takes. You can decide if the presence of inclusions bothers you or not, but if they can't be seen with the naked eye they don't affect the beauty of the diamond, only the price.



     There is one more aspect to buying a loose diamond: the unofficial fifth "C" of certification. We use the language of diamond grading so that we are all speaking in the same terms, but as you can imagine, it's important to know who has graded the diamonds you are considering. Independent gemological laboratories are the absolute best source. Once they have graded a diamond they produce a certificate listing all the diamond's grades and characteristics. An independent lab is important because they have no interest in the final sale of the stones they grade. Also, if different stores show diamonds graded by the same laboratory, people will know the same standards have been applied to each stone. We buy diamonds with certificates from one of three laboratories, and each lab has a certain character associated with it.

AGS (American Gem Society) is the most descriptive of the three major laboratories. Along with color, clarity, measurements and a diagram of the diamond's inclusions, they provide a diagram with the exact angles and percentages for the diamond. Diamonds certified by AGS do tend to cost a little more.


GIA (Gemological Institute of America) grades many stones and has a solid reputation. Their certificates don't offer as much information as AGS, but they are the industry standard.

EGL (European Gemological Laboratory) is known and recognized worldwide on a similar level to the above named laboratories.



     Having said that, there is one advantage to buying an uncertified diamond, and that is cost. Uncertified diamonds cost less because no one had to pay for a certificate. So how do you know for sure that you're getting what you paid for? A bit of knowledge, a look in the microscope, and a certificate go a long way. But ultimately, pick a jeweler you trust. Go back to Top