Consider the FOUR C's

In testing a diamond, there are really THREE 'C's, one 'M' and an 'F'. As you may know from your own experiences, buying a diamond can sometimes be confusing, and at times a little discouraging. It's often an experience that can lead to a lot of anxiety. After all, you're spending quite a lot of money!

Please take the time to read the following explanation of the Four C's of diamonds before we go any further.

Diamonds are graded by the use of what we call the Four C's - CUT, CARAT WEIGHT, CLARITY and the COLOUR.

The Cut

You must not mistake the cut for the shape of the diamond. Within the jewellery trade, on this web page and in the AUSCERT Diamond Certificate, the CUT is referred to as the MAKE.

The Carat Weight

A diamond's weight is expressed in carats. Carats are further split up into smaller units called points. There are 100 points in 1 carat. Thus a quarter carat diamond can be referred to as a 25 pointer and a 75 pointer is a three quarter carat.


When examined under 10-power magnification by an experienced grader, most diamonds reveal small natural markings or flaws.

The diamond's clarity is generally determined by the length of time it takes to find inclusions (internal) or blemishes (external) in or on the stone.

Also taken into consideration are such things as the size, number, brightness, colour and placement of the inclusions or blemishes, in or on the diamond. A standard grading system is now accepted universally. It is based on a scale ranging from "flawless" to "imperfect". Here's how it goes :

  • FLAWLESS (FL) completely free from all inclusions and blemishes at 10 times magnification.
  • INTERNALLY FLAWLESS (IF) flawless with only insignificant surface blemishes.
  • VVS1 & VVS2 (very, very slight inclusions): minute inclusions, ranging from externally difficult to quite difficult to see.
  • VS1 & VS2 (very slight inclusions): minor inclusions, ranging from difficult to more easily seen face up at 10 times magnification.
  • SI1 (slight inclusions-first degree): when a trained eye views the stone at 10 times magnification, inclusions are fairly easy to see.
  • SI2 (slight inclusions-second degree): when a trained eye views the stone at 10 times magnification, inclusions are quite easy to see.
  • I1 or P1 (imperfect or included-first degree): inclusions are visible to the naked eye when viewed through the top of the stone.
  • I2 or P2 (imperfect or included-second degree): inclusions are easily visible to the naked eye.
  • I3 or P3 (imperfect or included-third degree): prominent inclusions are extremely easy to see with the unaided eye.


A diamond's true colour can only be determined when the diamond is unset. Colour is graded with the use of master stones under special light (equivalent to Northern daylight.) A truly colourless diamond is extremely rare; most diamonds possess various degrees of yellow or brown. Letters, starting with D and working all the way down to Z represent a diamond's colour. Back to Top


Make is often overlooked but probably the most important 'C' of them all. And it's not even a "C"; it's an "M"! Firstly, the Make displays the art of the diamond cutter's skill and workmanship. It allows the hidden brilliance, sparkle and fire of the diamond to escape. A poorly cut diamond will look lifeless, dead and worst of all, glass-like. Secondly, the Make is an exact science, conforming to strict angles and proportion calculations.

The cut of the diamond is the only property that is totally dependent on human intervention. Thus it is also prone to human error and the desire to retain as much stone weight as possible from the diamond's original rough state. This boosts profit margins.


It is amazing that fluorescence is almost always overlooked, especially when it can dramatically affect the appearance and the price of a diamond.

Fluorescence naturally occurs in some diamonds. It is graded under long wave ultra-violet light. A diamond that has a medium-to-high, high, strong or very strong blue florescence can make the whitest diamonds appear milky blue or oily blue in appearance, dulling the stones brilliance.

But it is not all bad news! Some stones of an "I" colour for example, have been known to appear whiter than they are if the diamond has a faint or slight fluorescence.

Information as found on Auscert