What are the 4 C’s of buying a diamond?

Diamonds are the greatest essence of romance. You wouldn’t simply walk into a store and pick the first one you see. Diamond jewellery, especially engagement rings, should be chosen with extreme care and thought.

That means that when you are shopping for diamond jewellery, there are some important considerations to make (above and beyond your budget) that will determine the value and quality of your diamond.

The 4 C’s of purchasing a diamond were created as a universal language for identifying and classifying the quality of a diamond. Since each diamond is completely unique to the next, just like a snowflake, there needed to be a globally accepted standard for characterizing diamonds.

Consequently, the 4 C’s of diamond buying became the norm. Now, before you purchase  a diamond, it is essential to become educated on the 4 C’s so that you know exactly what type of diamond you are getting, or most likely, giving.

Simply put:

Cut, Clarity, Colour, and Carat.

These four categorizations will determine the quality of each and every diamond you purchase.

Diamond Carat

Different from a Karat, which refers to the quality of gold, a carat or the carat weight refers to the size or mass of any diamond. Each carat is equal to 200 milligrams or 0.2 of a gram.


In order to determine the exact size of a diamond, a point scale was introduced. Here, a point is equal to 1/100th of a carat. This allows for an exact measurement of a diamond up to the hundredth decimal point.

You may have heard the term used like this: a 50-point diamond, which refers to a 1/2 carat diamond.

In the instance of carat weight, bigger does not necessarily mean better.

However, sometimes the size of a diamond does indicate rarity, and therefore, price. Even more interesting, a diamond that is 0.99 carats versus exactly 1 carat in size are extremely hard to tell apart visually, but the difference in price can be quite significant.

Depending on the other 3 C’s (cut, clarity, and colour), the value is not directly linked to size alone. Values can differ between diamonds that are technically the same size.

For example, a large diamond that is cut poorly will not even begin to compare to a smaller diamond with a brilliant cut. Same goes for a large diamond with poor colour or clarity.

This is why it is incredibly important to educate yourself on all 4 C’s before purchasing a diamond.


Diamond Cut

Commonly mistaken as the shape of a diamond, in this case, cut actually refers to the how well a diamond’s facets interact with light.

This is a little confusing considering that the diamond industry uses ‘cut’ both ways. One refers to the shape, like Emerald Cut or Princess Cut, and the second usage refers to the reflectiveness quality described above.

Cut is by far the most difficult to analyze of all 4 C’s. Cut is determined by observing each and every facet of the diamond, including how well proportioned the facets are and how they react to light.

There are three different reactions to light that are taken into consideration:

Brightness – This refers to the internal and external white light reflected in each diamond.

Fire – Refers to the scattering of white light into all colours of the rainbow.

Scintillation – Is the amount of sparkle produced, as well as the pattern of light and dark areas caused by reflections within the diamond.

The cut grade, which range from Excellent to Poor, also considers the diamond’s design and craftsmanship, the symmetry of its facet arrangements, and the quality of polish on those arrangements.

A lot of times a poorly cut diamond is a result of the cutter sacrificing quality in order to create a larger sized diamond. Most diamonds sell by weight. However, not all diamond cutters make this sacrifice and their artistry does significantly increase the beauty of the diamond.

When purchasing a diamond, look for those with a rating from Excellent, Very Good, or Good. This will ensure you buy a brilliant, sparkling diamond.

Diamond Clarity

Since diamonds are unique in their nature, they also tend to have their own individual set of flaws. These flaws or ‘inclusions’ can be a variety of things including air bubbles, cracks, or other minerals all trapped within the diamond itself.

Each and every diamond is examined at a 10x magnification, and naturally, the fewer flaws or inclusions there are, the more valuable it is.

Another common flaw is referred to as a ‘blemish’, which occurs on the outside of a diamond. These are usually scratches, pits, and chips.

Again, clarity has its own particular grading system as follows:

  • Flawless (F) – Extremely rare, these diamonds do not have any inclusions or flaws, either internally or externally.
  • Internally Flawless (IF) – Minor blemishes on exterior, no inclusions.
  • Very, Very Slightly Included (VVS1 and VVS2) – Very slight inclusions, hard for even a skilled grader to identify.
  • Very Slightly Included (VS1 and VS2) – Minor inclusions can be seen with effort.
  • Slightly Included (SI1 and SI2) – Inclusions are noticeable under 10x magnification.
  • Included (I1, I2, and I3) – Inclusions are obvious under 10x magnification and could affect the transparency and brilliance of the diamond.

To the naked eye, it is almost impossible to see many inclusions or blemishes, but the clarity can impact the overall quality of your diamond.



When shopping for a diamond, anything in the VVS to VS grades are considered an excellent choice. For those on more of a budget, diamonds graded at SI1 and SI2 are considered ‘eye clean’, meaning that flaws are not noticeable to the naked eye.

Even though not all flaws are considered equal, we wouldn’t recommend anything with an I1-3 rating because flaws can be noticed by an untrained observer.




Diamond clarity chart by Boulevard Diamonds

Diamond clarity chart by Boulevard Diamonds

Diamond Colour

Funnily enough, when speaking of colour in regards to diamond quality, it is actually the lack of colour that determines quality.

Most of the time, the closer a diamond is to being completely colourless, the more valuable it is.

However, the exceptions to the rule are ‘fancy’ coloured diamonds in hues like pink, canary yellow, blue or green. These are considered extremely rare, and therefore, extremely expensive.


The colour scale starts at D and goes to Z. D to F being classed as colourless, G to J being near colourless, K to M being faint yellow, and finally N to Z ranges to very light yellow.

Most of these colour ranges are difficult to tell apart, but can vastly impact the value of your diamond.


Diamond Colour chart by Boulevard Diamonds

Diamond Colour chart by Boulevard Diamonds

Why do the 4 C’s matter when choosing a diamond?

We get asked this a lot, and while we agree that buying a diamond is a completely personal choice, it does help to have a bit of education to help you make an informed decision.

We want each and every one of our customers to feel completely confident with their diamond purchase. Learning the 4 C’s of purchasing a diamond before you go shopping can help with that.

For service you can trust, either call Boulevard Diamonds at 780.756.1230 or come visit us in-store!