Around the world, diamonds are seen as a symbol of love and commitment. Formed from a single element, Carbon, they are the hardest substance known to mankind and the purest gemstone we have. Despite their remarkable hardness, they are extremely brittle and should thus be treated with care. A rough diamond may seem dull and lifeless, but in the hands of an expert cutter, this rough is transformed into a polished stone exploding with fire and brilliance.

When purchasing a loose diamond, pay attention to the diamond grading guidelines, known as the 4C’s of diamonds, to make sure you’re getting your perfect diamond. All loose diamonds over 0.25ct in size should be certified by an independent diamond laboratory such as the GIA or the EGL.

Diamond Cut

Arguably the most important of the 4C’s and, as a result, the one we we pay most attention to at Katannuta Diamonds, an Excellent cut cut diamond will possess much more fire and brilliance than a poorly cut diamond. In an Excellent cut diamond (also often called an “Ideal cut”), the geometry and proportions of the facets are such that light entering through the table of a diamond travels to the pavilion of the diamond and is reflected to the other side before being reflected back out of the table of the diamond. There is 100% reflection of light back out of the diamond, providing maximum sparkle.
Often, diamond cutters will sacrifice the ideal diamond proportions in order to maximise the carat size of the stone. In cases like this, the diamond will appear dull and lifeless compared to an excellent cut stone. We will preferentially supply only “Excellent” and “Very Good” cut stones to our clients.

Diamond Carat

A carat is the unit of measurement used to weigh diamonds and other gemstones and is equivalent to 0.2g, or 1/5th of a gram. Due to the rarity of larger diamonds relative to smaller diamonds, larger diamonds consequently have a greater value per carat. As a result of this, the price of a diamond rises exponentially relative to its size. When deciding what size diamond to purchase, it is important to bear in mind both your available budget and the proposed setting for the diamond – a good setting can visually enhance the size of a diamond.

One of the easiest ways to save money when purchasing a diamond is to know where the price breaks are relative to the size of the diamond. If you are able to find a diamond in the upper-bracket of a particular size category, you will probably be able to save a significant amount of money without necessarily seeing a size difference in the diamond. A great example of this is the difference between 0.90cts and 1.00cts; the fraction of a millimetre size difference will almost certainly not be visible to the naked eye, but the 0.90ct diamond will be significantly cheaper.

Diamond Colour

The colour of a diamond is determined by its composition. A perfectly colourless diamond contains no impurities and allows more light transmission than a coloured diamond. True colourless diamonds are extremely rare and as a result are considered more valuable than slightly tinted diamonds.

Colourless or near-colourless diamonds are graded on an alphabetical scale that begins with D for top colourless diamonds. Fancy coloured diamonds are prized for their vivid colours, which may range from blue to yellow to pink. These are exceptionally rare and command high market prices.

As the scale moves through the alphabet to Z, diamonds contain increasing traces of yellow tint, due to increasing nitrogen impurities in the stones. Commercially sold diamonds tend to be available up to M colour with most retail outlets supplying diamonds in the G/H/I/J colour categories. Although diamonds graded D through F are considered to be of top colour and hence more desirable , diamonds graded G through I show very little visible colour to the untrained eye.

The visible colour of a diamond is also strongly impacted by the setting of the diamond. A white metal setting setting such as platinum or white gold will show off a colour quite easily, but in contrast a yellow gold setting may disguise a more yellow stone with the warm complimentary tint of the metal.

Diamond Clarity

The clarity of a diamond refers to the presence of natural inclusions within the diamond. Diamonds containing no inclusions are rare and, as a result, more expensive than the rather more common flawed diamonds. The clarity of a diamond is graded using a 10x magnifying loupe and range from flawless (F; no inclusions or external blemishes) to Included 3 (I3) where inclusions are visible to the naked eye.

  • F – Flawless: No internal or external flaws; extremely rare.
  • IF – Internally Flawless: no internal flaws, but some surface flaws; very rare.
  • VVS1 – VVS2 – Very Very Slightly Included (two grades): Inclusions very difficult to detect under 10x magnification by a trained gemmologist.
  • VS1 – VS2 – Very Slightly Included (two grades): Inclusions seen only with difficulty under 10x magnification.
  • SI1 – SI2 – Slightly Included (two grades): Inclusions easily detected under 10x magnification.
  • I1 – I2 – I3 – Included (three grades): Inclusions visible under 10x magnification and to the naked eye.

Almost all commercial-grade diamonds sold in retail stores will fall into the VS to SI category, with some certainly being graded as I-category diamonds. One or two natural imperfections are not a bad thing, for the reason that most of the time they cannot be seen with the naked eye and they can be used to identify your diamond as your own stone, should you be concerned about “stone swopping” at some retail jewellers.

Most noteworthy with regards to clarity is to understand that the natural imperfections can range from colourless to black and, in some rare instances, even coloured. Black inclusions (such as sulphides and graphite) will naturally be easier to see than colourless “feathers” or “clouds” in a diamond. While purchasing diamonds online is a a growing market niche, we would certainly recommend examining a diamond yourself, whenever possible, to see what colour and types of inclusions your chosen diamond possesses.

Diamond grading 4C's

At Katannuta Diamonds, we believe diamond education is one of the most important services a company can offer. When considering your once-in-a-lifetime engagement ring purchase, it’s critical to understand every aspect of the diamond, to make sure you’re getting exactly what you’re paying for.

We’ll make sure that the diamond you purchase from us is independently certified and that you understand the importance of each of the 4C’s, and how they relate to each other. Browse our range of diamond engagement rings and then contact us for your private diamond consultation.