Choosing The Perfect Diamond

When you start shopping for that once in a lifetime gemstone you might be surprised at the complexities behind choosing a diamond. The first decision you have to make is the shape of the diamond, followed by the famous 4Cs, cut, colour, clarity and carat.

Let’s take a look at each in turn.

Diamond Shape

Diamond Shape

The most popular diamond shape for an engagement ring is round, but princess-cut is also a solid choice. Other rarer shaped diamonds include oval, emerald-cut, marquise-cut, radiant-cut, Asscher-cut, heart-shaped, and pear-shaped.

Think about the length and width of your girlfriend’s hands and fingers when choosing your diamond shape. While a round or princess-cut diamond may look just right on long slim fingers, an elongated shape such as an oval or emerald-cut may work better on shorter wider fingers.

Diamond Cut

Of all the 4Cs, the cut of the diamond has the greatest impact on its appearance and sparkle, and so you should choose the best cut you can afford, even if you need to sacrifice a little colour or clarity. Getting the right cut for your diamond will really breathe life into it, whatever its clarity or colour.

The cut affects the way the light reflects off the diamond, and therefore the way we see it. In a perfectly cut diamond, all the light bounces back and emerges through the top, giving maximum sparkle. With a diamond that is cut too deeply, the light may escape out of the sides, and with a shallow cut diamond, light may pass straight through and be lost through the base.

Diamond cut classifications include poor, fair, good, very good and ideal. You should aim for at least a good cut if you can afford it.

Diamond Colour

You may think that all diamonds are white, but they vary greatly in their degree of whiteness. Most of the diamonds we see actually have a slight yellow colour.

Diamond Shape
Although we describe this characteristic of diamonds as their colour, what we are actually measuring is their lack of colour. A totally colourless diamond is very rare, highly sought after, and very expensive. However there are plenty of diamonds that have so little colour that it is undetectable to the naked eye.

The colour grade of a diamond is given using an alphabetic scale as follows:

D Completely colourless and very rare
E-F Colour traces can only be found by a gemmologist
G-H Colour exceptionally hard to detect with naked eye
I-J Colour very slightly detectable as warmth or tone
K-M Noticeable yellow colour
N-Z Strong noticeable colour

Colour grades D-F are very rare and extremely expensive. Looking for a diamond with a colour grade G-J is a good option as they will be more affordable, but the colour is hardly noticeable to the naked eye.

Diamond Clarity

Tiny natural imperfections can be found in all but the rarest of diamonds, and clarity is a measure of the size and number of these imperfections. Although the scale of clarity may appear complex, many experts believe that clarity does not have a great impact on a diamond’s beauty, and that it is acceptable to sacrifice some clarity for a better cut.

Gemmologists often refer to imperfections in diamonds as inclusions, and a diamond with imperfections is described as included.

Diamonds are graded for clarity according to the following scale:

FL / IF Flawless / Internally flawless
VVS1 / VVS2 Very very slightly included
VS1 / VS2 Very slightly included
SI1 / SI2 Slightly included
I1 / I2 / I3 Included

The first two categories are very rare and expensive so unless you have a large budget look for something in the very slightly included, or slightly included ranges.

Ideally you should look for a diamond with inclusions or imperfections that aren’t visible to the naked eye, and sometimes you can find diamonds which fit this description but are classified as slightly included and priced accordingly.

Diamond Carat

Diamond Shape
Many people believe that a diamond’s carat relates to its size, but it is actually its weight. 5 carats weigh 1 gram. To relate the carat to the size of the diamond, you would also need to measure the diameter of the top of the stone, and look at the cut as that determines its depth.

Diamond carats range from a quarter of a carat to five carats. Here are three tips to help you choose the right diamond weight:

  • Don’t be tempted to sacrifice your diamond’s cut to get a larger carat. A good cut can make a diamond appear bigger than it is because of the way it reflects the light so you are better off choosing a good cut and a smaller carat.
  • Diamond prices increase dramatically at the full carat and half carat points, so look for something just under a full or half carat. You will get better value for money and the size difference will hardly be noticeable.
  • Consider the size of your girlfriend’s hand when deciding on the carat of her diamond. A four carat diamond may look a little ridiculous on a petite hand, whereas a half carat solitaire may get lost on a larger hand.