Certified Diamonds
Our extensive trade network allows us to access thousands of polished diamonds in a variety of colours, clarities, carat and cuts. Our diamonds are certified by the most trusted international laboratories including GIA – Gemological Institute of America, HRD – Antwerp Institute of Gemmology and the IGI – International Gemological Institute. They have been verified for quality, allowing you to purchase with confidence based on the attributes of the diamond. A grading certificate issued by a reputable laboratory will give you an idea of what the diamond will look like without having to see it in person.
The 4Cs of Diamond
The value of polished diamonds is assessed according to four factors known as the ‘4Cs’:
Colour
Clarity
Cut
Carat weight
COLOUR
The majority of polished diamonds are graded for their lack of colour.
If one diamond can be shown to have a better colour (i.e. less colour) than another, of the same weight, clarity and cut, then it will have a higher value. If a diamond has a noticeable and attractive colour then it is classed as a fancy colour diamond. Fancy coloured diamonds are valued for their depth of colour rather than for their lack of colour and the price depends on rarity, beauty and demand. They can occur in almost any colour or shade including yellow, orange, brown, blue, green, pink and, very rarely, red.
CLARITY
The clarity of a diamond refers to a stone’s freedom from inclusions, which are characteristics found within the stone, and from surface blemishes. Clarity is graded on a scale of flawless to imperfect, as determined by an experienced grader using 10x magnification.
CUT
We can describe the quality of cut in different categories:
Proportions
Refers to the relationship between the sizes and angles of various facets (sometimes termed the ‘measurements’ of the stone)
Symmetry
Refers to the symmetrical appearance of the stone, e.g. the concentric positions of the table and the culet for a round stone
Polish
Refers to the quality of polish
CARAT WEIGHT
The word ‘carat’ is derived from the name of the carob or locust tree (Ceratonia siliqua) found in Mediterranean lands. The weights of loose stones are measured on carat scales.
Carat is denoted by ‘ct’:
1ct = 0.2 gram
5ct = 1 gram
For intermediate measurements, each carat is split into 100 points (pt):
1.00ct = 100 points
0.50ct = 50 points
0.01ct = 1 point
The greater the carat weight the higher the price, all other quality factors being equal, i.e. colour, clarity, and cut. There are certain desirable weights that cause a price jump. These magic weights are 1, 2, 3ct etc. so that a 0.95 carat diamond is worth far less per carat than a 1.01 carat diamond of the same quality (colour, clarity, cut).
GIA ANATOMY OF A DIAMOND
1. Star length 2. Table size 3. Girdle thickness 4. Crown height 5. Crown angle
6. Total depth 7. Pavilion depth 8. Pavilion angle 9. Lower half length 10. Culet size