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Diamond Classification Chart: What to Know Before You Buy

February 02, 2023

Diamonds are forever. So you want to ensure that you invest in the best gems that will stay timeless and valuable as they are passed on from generation to generation. But how do you know that your custom-made jewellery in Sydney contains an authentic and high-quality diamond? The answer lies in the four Cs: clarity, cut, colour, and carat—criteria that can also help with how to identify a raw diamond


Clarity measures the purity and rarity of the stone, plus the degree to which inclusions and blemishes are presented and how these affect the appearance of the diamond. 

Diamond Clarity Scale

Diamond clarity is graded based on a scale of Flawless (F) to Included (I).

Flawless (FL)

Flawless diamonds have no inclusions nor blemishes visible at 10X magnification.

Internally Flawless (IF)

An internally flawless diamond is similar to FL ones, but can contain very minor blemishes naked to the untrained eye.

Very Very Slightly Included (VVS1 and VVS2)

Diamonds graded as VVS1 have pinpoints that only a strong microscope can reveal, while one classified as VVS2 will have many smaller-sized spots, though still only visible using a microscope.

Very Slightly Included 1 (VS1 and VS2)

The inclusions in VS1 diamonds can be seen even without the use of a microscope. However, they’re still tiny and aren’t visible to the naked eye. VS2 stones are almost the same, with inclusions that are nearly always clean.

Slightly Included 1 (S1 and S2)

At S1 and S2, the inclusions and blemishes of a diamond, usually several small spots and clouds of tiny dots, become apparent to the human eye—though they will still look clean. In most cases, the negative characteristics are only visible when used with other dazzling forms.

Included (I1, I2, I3)

Similar to the Slightly Included diamonds, I1 diamonds have inclusions and blemishes that are visible to the human eye and are increasingly apparent with certain cuts. Those with even more pinpoints fall to levels I2 and I3, though there isn’t a big supply of these diamonds because demand is low.


A diamond’s cut measures how the stone facets interact with light to allow it to sparkle so intensely. It requires precise artistry and workmanship to fashion the most well-proportioned and symmetrical diamond to transmit the most light.

Diamond Cut Grading

Diamond cuts are graded based on the following scale:


Excellent cut diamonds are the most sparkly because almost all of the incoming light is reflected through the stone.

Very Good

Very good cut diamonds provide a similar sparkle to those of Excellent grade when seen by the naked eye. Though they reflect a slightly lower amount of light.


Good cut diamonds have great brilliance and sparkle, though because they don’t reflect as much as the two higher grades, they come at a lower price point.


Fair cut diamonds offer little brilliance. They’re usually chosen as side stones or for smaller carat gems.


Poorly cut diamonds almost don’t sparkle at all. Instead, any entering light escapes from the sides and bottom of the stone.


Interestingly, the evaluation of a diamond’s colour is based on the colour’s absence. The more chemically pure and structurally perfect the diamond is, the higher its grade, which is measured from a scale of D to Z and is ascribed by comparing the stone under controlled lighting and viewing conditions to master stones of established colour value.

Diamond Colour Grading

Here’s a breakdown of the diamond colour grading scale:

    • D to F: Almost completely colourless, with the differences only visible to an expert gemologist when the stones are put side by side
    • G to J: Nearly colourless; ranges from being colourless to the naked eye to have a slight yellow tint, with the latter only being obvious under certain light or magnification
    • K to M: Has a faint yellow tint that’s visible to the naked eye under normal lighting conditions, but comes at a cost-effective price
  • N to Z: Have a noticeable yellow or brown tinting and aren’t usually recommended for jewellery

It’s important to note that coloured diamonds don’t fall under this grading system.


A diamond’s carat measures its weight. All else equal, the heavier the carat, the more valuable a diamond is because larger stones are usually rarer.

The Best Diamonds from Holloway Diamonds

Holloway Diamonds prides itself on offering a catalogue of expertly hand-picked diamonds, promising quality and value in every piece. Each purchase comes with a GIA certificate (so you don’t have to look up how to get a valuation certificate for jewellery), plus HCA and Ideal-Scope assessments, so you’re sure you’re walking away with a stone worthy of several lifetimes!

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