Diamond Grading
The ultimate diamond grading guide - know the famous 4 C's
The 4C’s – Carat, Color, Clarity and Cut – are the global standard grading system that provides an objective way to assess and describe the quality and value of a diamond.
By considering these four factors, buyers and industry professionals can accurately evaluate and compare diamonds to help make informed decisions about their purchase or appraisal.
Specifically, the 4C’s all contribute to determining the value of a diamond. Diamonds with higher grades in the four C’s, such as excellent cut, colorless color grade, higher clarity, and larger carat weight, tend to be rarer and more valuable, resulting in a higher price. Conversely, diamonds with lower grades in these categories may have a lower price due to lower rarity and desirability.
CarAt (weight)
Carat refers to a diamond’s weight—and it’s one of the biggest drivers of price. The term dates back to ancient times when carob seeds were used as natural weight standards. Today, one carat is equal to 0.2 grams, measured with precision down to the hundredth.
While weight isn’t the same as visible size, it strongly influences pricing. You’ll often see noticeable price jumps at 0.5 ct, 1.0 ct, 1.5 ct, and 2.0 ct. For reference, a well-cut 1.0 ct brilliant round diamond typically measures 6.5 mm in diameter.
Clarity (presence of natural imperfection)
Clarity describes the presence—or absence—of natural imperfections in the diamond. These can be inclusions (internal) or blemishes (surface). Most are microscopic and have little impact on beauty, but they do affect rarity and price.
The GIA clarity scale is the industry standard:
Flawless (FL): No visible flaws under 10x magnification
Internally Flawless (IF): No inclusions; only minor surface blemishes
VVS1 / VVS2: Very, very slight inclusions, barely visible under magnification
VS1 / VS2: Very slight inclusions, visible only with effort
SI1 / SI2: Slight inclusions, sometimes visible with a loupe
I1 / I2 / I3: Inclusions visible to the naked eye
For fine jewellery, VS1 or VS2 often strikes the ideal balance—imperceptible to the eye, but more approachable in price than flawless grades.
GIA CLARITY SCALE
Colour
Diamonds are graded on a scale from D (colourless) to Z (noticeable yellow tint). The less colour, the rarer—and more valuable—the stone.
While D to F are considered colourless, we often recommend G or H for the best value. These diamonds appear white in natural light but offer a more accessible price point. Beyond Z, diamonds fall into the fancy colour category (such as vivid yellow or pink).
GIA COLOR SCALE
Cut of the diamond
Cut is what brings a diamond to life. It’s not about shape, but rather how well the stone is proportioned, polished, and faceted to reflect light. A well-cut diamond captures and returns light with brilliance, fire, and sparkle.
Cut is graded from Excellent to Poor. We always recommend choosing Excellent or Very Good cuts—these maximise light performance and give your diamond its signature glow. Even a high-carat, flawless stone will appear dull if the cut isn’t right.
