Buying a Diamond

Diamonds are forever, a girl’s best friend, the hardest substance on earth, the sparkle in the eye of the beholder; they’re April’s birthstone and statistically chosen more often for engagement rings than any other stone. Due to their sparkle, their durability, and ability to retain value—they’re a good choice! In this guide, I’m going to share my recommendations for choosing and purchasing the perfect diamond for you.
Tip—jump to the TL/DR section at the end for a quick guide!


A quick Google search will lead to results emphasizing the four C’s—cut, colour, clarity, and carat weight—and Google isn’t wrong! These things have a lot to do with the overall look of a diamond. When speaking with my clients, I emphasize two other C’s that are very important—Certificate and Cost. Stone certificates detail the properties of a specific diamond and should always come from a reputable lab. These reports are an unbiased grade on which to base the quality and value of a stone. The Gemological Institute of America (GIA) is the most internationally renowned laboratory and inventor of the diamond grading system used worldwide. Because GIA graded stones retain their value and their reports are trusted globally, my father and I insist on buying diamonds accompanied by GIA reports.

Don’t worry, I didn’t forget Cost! I’ll discuss this in greater detail at the end; just know that having a clear idea of budget in mind will make this process easier.

What gives a diamond it’s sparkle? Let’s check out the four visual properties mentioned above—cut, colour, clarity & carat weight:


Of the four, I recommend considering cut first. Cut grades share with us the proportions, symmetry, and polish of the stone; the reason a diamond sparkles is because of the light entering and bouncing off the cuts and facets within the gem. Only stones with a high cut grade can show the levels of brilliance, fire, and scintillation that we want from a diamond. The grading system one will find on a GIA certificate is as follows:

Excellent>Very Good>Good>Fair>Poor

A properly proportioned stone (within the Very Good to Excellent range) will give the greatest light return. The qualities we have come to love in a diamond—namely that sparkle!—come from this carefully calculated reflection of light.

The GIA is working to come up with cut grades for fancy shapes. Currently only round brilliant diamonds have this specification. Fancy cuts (princess, marquis, oval, radiant, etc.) will still have a polish and symmetry grade that is important to consider.


Colour is the next most noticeable feature of a diamond for an untrained viewer. The GIA grades its colorless diamonds on a scale from D-Z. On one side of the scale are the most colorless, D though G, that lack eye-visible color; as we progress down the scale, the nuances of yellow and brown become more and more visibly apparent until we reach Z, the most brown/yellow a diamond can be while still being considered on the colorless scale. When advising my clients, I recommend staying between the D to G colour range when possible, while also considering budget and other specifications like stone size.


It may surprise some that I place clarity this far down on the specifications list, but don’t be fooled, it doesn’t mean that it isn’t important! It is simply only important to an extent. Clarity is graded on the following scale:

Flawless>internally flawless>VVS1>VVS2>VS1>VS2>SI1>SI2>I1>I2>I3

The reason clarity is third is because on the scale from SI1 up to Flawless, the probability of being able to see the internal imperfections of the stone with the naked eye are low. For the overall look, choosing an SI1 (even sometimes an SI2!) and above is a safe choice and allows a little more wiggle room on a tight budget. Keep in mind, that the higher clarity grades fetch a higher price and maintain a higher value due to increased light return. But to keep it budget friendly and still get a great look? Choose an SI1 or higher.


Carat weight is the size of the diamond, and suffice to say, size isn’t everything! The reason I put this last is because ideally the size of stone one can afford should be decided after setting parameters for the other qualities above. A two-carat stone with a poor cut grade, N colour, and I1 clarity is not going to be a fantastic looking diamond. It may be the right ‘size’, but the light return is going to be extremely low, the tones of yellow and brown will be high, and the inclusions inside will be visible to the unaided eye. Remember this: size is definitely noticeable, but a big stone that has no life and a low colour grade will always be noticed and not in a good way. A smaller stone with greater sparkle (with higher cut, colour and clarity) will dance in the daylight.


So how much does a diamond cost? The cost of a diamond is based on the grades the stone is given in the above categories—which is great! This means that trained diamond buyers, like my father and I, can tweak and adjust the specifications to find a beautiful diamond that meets the budget—just make sure to have a budget in mind.


Having a trusted graduate gemologist, especially one trained at GIA like my father and I, as a guide through this process is a way to safeguard a diamond purchase. The diamond industry is a global market that deals in materials of high value. Like other similar industries, dishonesty isn’t unheard of. If it sounds too good to be true? Be wary, it probably is. More than once a client has found a “better deal,” but this “better deal” simply meant that quality was sacrificed somewhere, and often without disclosure. We here at Maison Goldberg bring transparency, integrity, and value to our clients and their purchases—but many in the industry do not. We want to help match our clients with the finest stone their budget allows. Find a trusted source and educate yourself; cheers to the sparkle ahead!

– Keely


  1. CERTIFICATE: Only consider diamond certified by a reputable source (like GIA)
  2. For the overall look/value of a diamond, consider the 4C’s in the following order:
    1. Cut>Colour>Clarity>Carat Weight
  3. CUT: Avoid cut grades below very good (including polish/symmetry) as the poor proportions will reduce overall look and brightness
  4. COLOUR: If possible, keep the choice of colour between D and G, depending on budget
  5. CLARITY: Choose clarity grades in the SI1 range or above (nothing in the “I” range!)
  6. CARAT: Decide how far the budget can go on size after determining parameters for the C’s above
  7. COST: Have a clear budget in mind, a well-trained gemologist will be able to adjust the specifications listed above and select the finest stone a budget allows
  8. CAUTION: If it sounds too good to be true? It probably is. Find a trusted, well-trained, graduate gemologist to be a guide through the process!
Diamond Illustration