Choosing a Diamond
The 4C’s
• Cut
• Clarity
• Color
• Carat Weight
Cut
• Cut is the most important factor to a diamond's beauty. Regardless of the color, clarity, and carat weight, a well-cut diamond will be beautiful.
Shapes of Cuts
• Ability to reflect and refract light• Four factors
– Luster – quantity and quality of reflecting light– Brilliance – amount of light returned to the eye
from the diamond– Dispersion – amount of rainbow colors returned
to the eye from the diamond– Scintillation – the sparkle when there is
movement by the wearer or a light source
Optical Beauty
Cut Diagram
• There are 57 or 58 angled planes called facets in a good cut that release the brilliant colors of a diamond.
Ideal Cut
•Light entering the diamond reflects internally from facet to facet and is reflected back through the top only
•Optimal proportions, with optimal polish and symmetry•Produces maximum luster, brilliance, dispersion, and scintillation. •Most valuable (only 5% of the round brilliant diamonds)
Inferior (Deep) Cut
• Will appear smaller than it weighs because it's weight is retained in the depth.
• It is cut with a deep pavilion (bottom of the diamond) that does not reflect light back through the crown (top of the diamond).
• Light leaks out the pavilion brilliance is lost and the center of the diamond will appear to be dark.
Inferior (Shallow) Cut• Do not reflect light back through
their crown, light leaks out of the bottom.
• Produces a washed-out or watery appearance that is not beautiful.
• These diamonds are sometimes called fisheyes, due to unsightly reflections in the crown area.
• Weight is retained in the diameter, making the diamonds appear larger than they weight.
Cut and Relation to Value• Cut quality commands a premium for two reasons.
First, you are paying for a highly skilled diamond cutter's time, and it can take many hours to get all the proportions and angles to fall within the Ideal or SuperIdeal ranges. Second, more of the diamond is lost in the cutting process, because the goal is not to cut the heaviest diamond, but the best performing diamond
• Cut can affect the value by 25% to over 50%. • Fancy-shaped diamonds, since they retain weight
from unusual shaped rough crystals, are often less expensive then comparable round diamonds.
Color• Amount or presence of body color in a diamond.• Diamonds come in all colors.• The most rare diamond colors are red, pink, green,
and blue.• The absence of color in diamonds is most rare.• Most diamonds mined in nature have traces of yellow,
some brown or gray.• Color is caused in diamonds by minute traces of other
elements, such as nitrogen = yellow and boron = blue.• Color is an important factor to beauty, rarity, and value
because it is something a consumer can see without the aid of equipment.
Diamond Fluorescence
• A unique quality possessed by some diamonds to give off light when exposed to specific ultraviolet wavelengths. It is an unusual quality that can enhance the appearance of a diamond in certain.
• Very strong fluorescence may produce an oily appearance that detracts from beauty and value.
• Only 50% of all gem-quality diamonds fluoresce, and only 10% strongly fluoresce. When gem-quality diamonds fluoresce it is a bluish color.
Color Scale
• Colors D, E and F are essentially without color and differ more in transparency.
• Colors G, H, I and sometimes J, will usually show little or no color.
Color and Price
• The more yellow the stone, the lower the value.
• Price can decrease by 5 - 20% on each increment of the AGS diamond grading scale.
• Prices fall about 25% in going from D to E color, and then about 10% more for each additional grade (F=-35%, G=-45, H=-55%) until one gets to H color, where the difference decreases to about 5% less going from H to I color (I=-60%).
Clarity
• A a measure of the surface (blemishes) and internal (inclusions) characteristics of a polished diamond, and has, as does color, a major impact on value.
• Clarity characteristics are an inherent part of a diamond's life, and can arise from events which occurred during its formation deep in the earth, the mining procedures used to collect it, the cutting of rough into its final shape and the wearing of the stone.
How Clarity is Graded• Using a 10x magnification
and also the assessment of the trained unaided eye.
• When a diamond is examined, the size, type, position, number, color, and relief of clarity features are observed.
Clarity and Price
• Going from IF to VVS1 clarity will result in about a 25% decrease in price, and a further 10% decrease for each clarity grade (VVS2=-35%, VS1=-45%, VS2=-55%) until SI1 and SI2 where 5% further decreases are in order (SI1=-60%, SI2=-65%).
• Clarity is a rarity factor that affects diamond value by 5 - 20% for each increment on the AGS diamond grading scale.
CARAT WEIGHT
• A measurement of weight used in determining rarity in evaluating a diamond.The term Carat is derived from the ancient Carob Seed from the locust tree, used as a medium of exchange on early pan-balances. In the early 1900's the Metric Carat was established.
• 1 Carat = .2 Gram• There are 100 Points to a Carat.
Carats and Cuts
• For well-proportioned, round diamonds a 1.00ct. stone should normally be about 6.5mm in diameter, a 3.00ct. would be 9.3mm, etc.
• However, if a 1.00ct. round diamond has a shallow cut, it will look larger than a well-cut stone of the same weight because its diameter will be larger than 6.5mm.
• Conversely, when a 1.00ct. round diamond is cut too deep, it appears to be of smaller size than a well-cut stone, because the diameter will be smaller than the expected 6.5mm. This means that you are paying for extra weight in the pavilion and girdle areas, which doesn't add to the beauty of the diamond.
Carat Weight and Its Relation to Value
• Carat weight usually has the greatest impact on value, based on rarity. Most people aspire to own at least a 1-carat diamond. DeBeers states, "fewer than 1% of all women will ever own a 2 carat or larger diamond".
• Most fancy-shaped diamonds are elongated in shape and appear larger than a comparable round brilliant diamond. In addition, fancy-shaped diamonds are priced less than round brilliants.
Miscellaneous Facts
• Eighty percent of the world's rough diamond supply are produced in seven countries, Botswana, Russia, South Africa, Angola, Namibia, Australia and Zaire.
• The most frequently found diamonds (~80%) are of industrial quality. Those suitable for gem use (~20%) usually have some yellow tint, due to the presence of a small amount of contaminating nitrogen.
Questions to Ask Jeweler
• Do you have a microscope (not just a loupe) so I can easily see the diamond under magnification?
• Do you have a set of diamond or CZ master color grading stones to compare the color of the diamond I choose?
• Do you have a GIA graduate gemologist in-house to answer my diamond questions?
• Do you have a full-spectrum diamond light for color grading (instead of the regular display lights that artificially enhance color)?
Questions to Ask Jeweler
• Is there a gemological report from an independent gem trading laboratory available for the diamond.
• Will you show me the Rapaport wholesale diamond price list for the diamond I choose?
• Does each diamond come with a grading certificate from one of the respected independent gem labs (GIA, AGS, or EGL)?
• Will you give me the full price if I want to trade the diamond later for a larger size?
• How long has your company been in the diamond business?
GIA and AGS Grading
• A final point about GIA and AGS grading reports. Diamonds graded by these labs. Carry about an 8% premium over those graded by other labs. Such as EGL, IGI, HRD, etc. The reason is due to their strict grading guidelines, which are respected and accepted worldwide. You can rest assured that if your diamond is graded by either GIA or AGS that the color, clarity, polish and symmetry are what the report says, so you know what you are paying for.
