The Diamond 4C's

Cut
The main diamond cuts are:
Round Brilliant
Emerald Cut
Princess Cut
Heart Cut
Oval Cut
Marquise Cut
Pear Cut
Round Brilliant

Popular diamond cuts include Heart, Emerald, Marquise (Oval with pointed ends), Oval, Pear, and Princess. There are unusual cuts appearing all the time such as the J C Millennium which is basically a Round Cut stone similar to the Round Brilliant, and the Radiant Cut which is an octagonal stone similar to an Emerald or Step Cut with upper girdle facets similar to the Princess Cut which is a square stone.

Cut The most popular cut is the modern round brilliant (R/B):


Round Brilliant Facets
The standard brilliant comprises:

Upper:
1 Table facet
8 Star facets
8 Kite or Upper Main Facets
16 Upper Girdle facets

Total facets: 33 Crown Facets

Girdle:
This is the waist band in the middle, and is sometimes faceted.

Pavilion:
8 Pavilion
16 Lower Girdle
1 Culet

Total facets: 25 Pavilion Facets

Thus there are 58 facets in total.

 



Color
There are many differing scales used by different organisations for color, but the most common one is an alphanumeric scale starting at the color D. This is the whitest color exhibited by diamond. To give you a feel for the colors we have prepared a table below:

Color: Description:
DPure White - the most prized color
EExceptional white - colorless group
FExcellent white - colorless group
GGood white - colorless group
HWhite - colorless group
ISlightly tinted white/ white when viewed from top
JSlightly tinted white/ commercial white
KTinted white/ still acceptable white when mounted
LTinted white/ needs yellow setting to look its best
MSlightly yellowish/Tinted color-champagne
NSlightly yellowish/Tinted color-champagne
O-RYellowish/Tinted color
S-ZYellow/Tinted color


Clarity
Clarity:Number and SizeExpert-10x loupeNaked EyeInfluence on Brilliance
IFno inclusions-internally flawlessnothingnothingnone
VVS1very very small inclusions, pin pricksvery difficultnothingnone
VVS2very very small inclusions, pin pricksvery difficultnothingnone
VS1very small, still minutedifficult to seenothingnone
VS2very small, still minutedifficult to seenothingnone
SI1tinyeasily seennothingnone
SI2tinyeasily seennothing from topnone
I1smallrecognisable immediatelydifficult to recognisenone
I2larger and/or numerous inclusionsobviousrecognisable immediatelyslight
I3large and/or numerousvery obviousvery easily recognisedheavy influence

Clarity is an indication of a diamond's purity. It describes the degree to which a diamond is free of imperfections. The internal clarity grades range from internally flawless (IF) to fairly included (I3)or third pique (pronounced peekay) also written P3.

Flaws in diamonds may include external blemishes (from naturals and polishing defects) and internal inclusions. Most blemishes are so small as to have no affect on the beauty or brilliance of the stone. In nearly all diamonds, traces of minerals, gasses or other elements were trapped inside during the crystallization process. Inclusions look like tiny crystals, clouds, or feathers and are unique to every diamond. It is very rare to find a diamond that is completely clean to the expert eye using magnification.

The clarity of a diamond is graded by how many, how big and how visible the inclusions are, and where they are located within the diamond. The fewer and smaller the inclusions, the more rare and valuable the diamond. It is very rare to find an internally flawless (IF) diamond.

Grading according to discernability of inclusions:
It can be seen that diamonds graded SI2 and better will appear to be perfect, and no loss of brilliance will be detected. Combined with a good cut and color of H or better, we have a perfect diamond for any piece of jewellery.

Enhancements
Laser Drilling
Lasers have been used commercially for drilling diamonds since the late 1960's. It is possible to improve the appearance of diamonds which have dark magnetic pyrites and magnetite inclusions by drilling into the diamond surface and then bleaching out or chemically dissolving the inclusions with an etching fluid such as sulphuric acid and saltpetre. The drill holes are then usually filled with a highly refractive wax or synthetic resin and this protects the drill chanel against penetration of dust and dirt. This can be affected if your diamond is ever subjected to heat or acid as often is the case when being set in jewellery or worked on by an unsuspecting working jewller. Although the treatment is fairly permanent, we will not sell you a diamond that has been drilled.

Filled Diamonds
This is a more recent enhancement by which inclusions and especially cracks which break the surface can be made more transparent and hence improve the clarity of a cut diamond. The cracks are filled under pressure (50 atmospheres) in a vacuum at high temperature (400 degrees Celcius) with a glass of refractive index close to that of diamond at 2.417. A color flash similar to that on the surface of a detergent bubble is visible due to the juxtaposition of the two different materials. Unfortunately the process though widely used is neither durable or permanent and will not withstand the cutting and repair processes involved in jewellery work. We will not sell you a diamond that has been filled.

Internet Shopping Precautions
The Internet is full of drilled and or filled diamonds, especially eBay! We strongly advise you to be extremely cautious when buying diamonds on the Internet auction sites.

Carat Weight
The weight of a diamond and is measured in Carats. 1 Carat equals 0.2 gram and there are 100 points to a carat. Thus a 50 point diamond is half a carat (0.50ct) and weights 0.1 gram. A Grain, no longer used, is accepted to be 0.050 grams. Many dealers still use the terms a grainer meaning 0.25ct, two grainer - half carat, six grainer- 1.5 carats etc.

There is an approximate relationship between weight and diameter of a round brilliant cut diamond. This is useful when trying to estimate the size of a diamond.

Weight: Size (diameter):Weight: pts (diameter):Weight: fractions
0.05ct1.00mm5pts1/20th
0.10ct3.00mm10pts1/10th
0.20ct3.85mm20pts1/5th
0.25ct4.10mm25pts1/4
0.33ct4.55mm33pts1/3rd
0.40ct4.80mm40pts
0.50ct5.15mm50pts1/2
0.66ct5.72mm66pts2/3
0.75ct6.00mm75pts3/4
0.90ct6.40mm90pts
1.00ct6.65mm100pts1 carat
1.50ct7.50mm150pts1 1/2
2.00ct8.10mm200pts2 carats

Most diamonds are accurately weighed on an electronic scale to the nearest 1000 th of a carat (0.001). If a stone weighs 0.009 it is rounded up and 0.008 is rounded down. This is standard practice in accordance with diamond club rules, but in all other industries 5 is rounded up and 4 is rounded down.

Example:
Weight 2.329 carats will be described as 2.33 carats.
Weight 2.328 carats will be described as 2.32 carats

According to Trading Standards, jewellers are technically allowed to round up at the 5, hence 2.325 carats rounds up to 2.33 carats but this is frowned upon in the trade.


Certificates
Where a diamond has been assessed by a laboratory it is termed a certificated or certified stone.

We sell diamonds issued with a EGL,GIA, IGI, AGS or HRD certificate, but other certificates may be available on request.

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