The 4 C’s of Diamonds
Cut of Diamond
Cut and shape have taken on the same meaning when discussing diamonds. This is not strictly correct.
There are many different shape diamonds but really just two cuts. There is the brilliant cut and step cut.
Shapes with step cut:
Shapes with brilliant cut:
Selecting a particular shape is a personal choice. Cut properly each one has its own distinct charm and beauty and will retain it’s value.
The brilliance and beauty lies ultimately in the hands of the cutter. The temptation to cut a diamond for heavier weight (rather than for elegance and brilliance) is the dilemma facing all manufacturers.
To produce beautiful diamonds the cutter must elect to apply the best proportion criteria and demand precise faceting and polishing from skilled craftsmen.
When cut correctly a diamond draws light into the stone from the top only, and will reflect a brilliance nothing else in nature can equal. Cut imperfectly, the light is not captured or reflected efficiently, resulting in less brilliance and lower value.
The GIA grades cut by assessing various proportions of the stone in relation to one another. The ideal range of proportions have been determined by assessing the light interaction in stones with various depths, width and many other factors. Another component to the cut grade is the finish of the stone which looks at the overall symmetry of the faceting and finally the quality of the final polish.
Q: Why are all diamonds not cut perfectly?
A: The market-place is driven by weight and cutters have financial incentive to produce heavier rather than more perfectly cut diamonds.
Work with a trusted expert who can illustrate and explain the finer points of cut and polish.
Colour of Diamonds
The more colourless a diamond the greater its rarity and value. The diamond colour scale begins with D (whitest) and descends to Z (considerable yellow)
The GIA describes colour as follows:
We recommend buyers select in the “D to J” range for two reasons: Whiter diamonds are simply more beautiful and the better colours have historically increased in value more rapidly.
Two diamonds with the same GIA colour grades will not necessarily face up the same to the naked eye. Every diamond is unique and shows colour and brilliance a little differently.
Interestingly, the same diamond submitted to the GIA for colour grading more than once will not necessarily receive the same grade each time. How is this possible?
Colour grade is judged on a spectrum and even though new electronic equipment can be useful, colour is a subjective call and it is understandable for a colour grade to be seen slightly differently at different times.
In addition it is interesting to note that while the GIA is a worthy institution they certify any diamond submitted for grading and make no comment on value or brilliance.
A diamond selected in the D to H colour range will not show any yellow tint… I and J colours will show just a hint. Buyers looking to own a larger stone (for the same money) can get very good value by selecting well cut I and J colour diamonds.
Beautifully cut diamonds face whiter and brighter.
Clarity of Diamond
Clarity grades attempt to define the quantity, size, and position of inclusions or blemishes in a diamond when examined under 10x magnification.
Below is the GIA clarity grading scale in descending order:
Flawless and internally flawless:
“Flawless” describes a diamond without any blemish or internal inclusion whatsoever.
“Internally Flawless” describes a diamond without internal inclusions but it might have a microscopic blemish on the surface that typically can be polished out. Both clarity grades are extremely rare.
VVS1 and VVS2 = Very very slight inclusions:
VVS clarities describe inclusions barely visible even under 10x magnification . A typical VVS inclusion might be a single microscopic white pinpoint. The difference between VVS1 and VVS2 could be the position of the inclusion… Closer to the girdle [edge of the stone] = VVS1 whereas closer to the center = VVS2.
VS1 and VS2 = Very slight inclusions:
VS1 and VS2 inclusions are barely detectable under 10x magnification. While VS inclusions are slightly more prominent than VVS they remain insignificant. Once again the difference between VS1 and VS2 relates to the size, color, and location of the inclusions.
SI1 and SI2 = Slightly included:
SI1 and SI2 inclusions are easier to detect under 10x magnification but should not be visible to the naked eye. These clarities (selected with care) are a good choice for buyers who prefer a slightly larger diamond for their budget.
I1 clarity = Included
Over time diamond merchants observed GIA “I1” clarity grades were covering too broad a range and felt the need for a grade between SI2 and I1. Gradually SI3 clarity and pricing worked its way into daily conversations between diamond merchants worldwide, until finally in 1989 SI3 became official, when the “Rappaport Diamond Report” included SI3 clarity on their weekly wholesale price list and it remains on the list to this day.
While the GIA doesn’t recognize SI3 we need to know how to judge whether clarity is SI3 or I1.
If the inclusions do not affect brilliance and the diamond is definitely eye-clean, SI3 is appropriate. However if the diamond has obvious visible inclusions, the appropriate clarity grade should be “I1”.
Finally: I2 and I3 = Heavily Included:
These clarity grades have heavy inclusions clearly visible to the naked eye.
To get a complete understanding of clarity we recommend looking at different stones with the guidance of a skilled expert.
Carat Weight of Diamond
“Carat”is the standard measure used for diamond weight. 1.00 carat = .20 gram.
Diamonds are priced “per carat” and the heavier the diamond the higher the price per carat. As a result carat is the most significant cost driver of the 4 C’s of Diamonds.
Example: Consider two identical quality and shape diamonds, a 1.00 carat and a 2.00 carat. If the price for the 1.00 carat stone is $6000, the 2.00 carat would be $7700 per carat, $15,400 for the stone.
Price per carat is related to rarity. Mother nature provides an adequate supply of diamonds .75 carat and below, but larger diamonds are truly scarce and become more rare as they get larger.
To recover a single rough diamond weighing 1.00 carat, a mine must process approximately 20 tons of earth, incredible but true!
A rough diamond will lose 30-60 percent of its original weight in the cutting process. The actual percentage loss depends upon the rough and the shape being produced. Therefore a 2.00 carat ‘rough diamond’ (on average) is required to produce a 1.00 polished gem.
The “price per carat” example above illustrates the incentive cutters have to produce heavier rather than more beautiful diamonds. Weight can be “added” to the girdle, crown, and pavilion of a diamond by manipulating the proportion. Unfortunately this strategy produces diamonds with a smaller ‘face to weight ratio,’ and less brilliance.
To protect the value of your purchase be sure to consider all of the 4 C’s of Diamonds, and allow a trusted expert to guide you through the selection process.