Diamond Buying Guide

What are the "four C's" relating to diamond quality?

The four C's are Carat (weight), Colour, Clarity and Cut of the stone.

1. Carat: The weight of the stone, referred to in points in case of small stones.
   • 1 carat is 1/5 of a gram or 200 milligrams.
   • There are 100 points to a carat.
   • A 75 point stone is .75 carat.
   "Carats" represent the weight and not the physical size of the stone. For example, a 1 carat diamond is physically larger than a 1 carat ruby since ruby is denser than a diamond.
2. Colour: Colour is usually undesirable in diamonds. Typically ratings will be alphabetical with the earlier letters of the alphabet having less colour.
   AGS has a similar 0-10 scale.
   
   • D, E and F - "Colourless"
   • G, H, I & J - "near colourless"
   • K, L and M - faint yellow or "top silver"
   • N to Z - very light or "light yellow"
   • Z+ - grades are considered "fancy yellow"

   Most stones you will find will be in the E-F to the J-K range.

3. Clarity: You will typically find ratings such as this:
   

   GIA	AGS	CLARITY
   FL	0	Flawless
   IF	1	Internally Flawless
   VVS1	1	Very, Very slightly included
   VVS2	2	VVS1 to a less perfect degree
   VS1	3	Very slightly included
   VS2	4	VS1 to a less perfect degree
   SI1	5	Slightly included
   SI2	6	SI1 to a less perfect degree
   I1	7-8	Included
   I2	8-9	I1 to a less perfect degree
   I3	9-10	Severely Included

   Inclusions are imperfections within the stone. Inclusions range from bits of carbon (black spots) to slight cracks (called "feathers") within the stone. VVS1 to SI2 represent inclusions that are not visible to the naked eye.

4. Cut: All diamonds are cut. The resultant dimensions of the cut stones vary. All dimensions are given as a percentage of the width at the girdle. There are a few accepted ideal cuts, which have all of the proportions within a few percentage points of an optimum mathematical model. This optimum model returns maximum light through the top of the stone, resulting in maximum brilliance.