Diamond Quality Characteristics
Choosing a diamond is all about personal taste and for most people buying a diamond is a new experience. Finding a beautiful diamond is easy; finding the right one for your taste and budget is more of a challenge. An understanding of the diamond's quality characteristics will allow you to consider the factors most important to you when choosing your diamond.
One of the most important elements of a diamond's appearance is the cut. The majority of diamonds are rarely cut to ideal proportions, but they have such high optical properties that most of them are still beautiful.
The way a diamond is cut will have the most significant effect on how the stone catches and interacts with light; what we generally think of as sparkle. A well cut diamond will reflect most of the light through the table (top surface) of the stone. If the diamond is cut too shallow or too deep then some of the light will escape out of the bottom or side.
Excellent Cut: The diamond has high brilliance, sparkle and an even pattern of light and dark areas. Most of the light entering the diamond is reflected back through the table.
Very Good Cut: The diamond has high brilliance and sparkle but down-graded by its pattern being a little bit darker in the centre or around the edges. Most of the light entering the diamond is reflected back through the table.
Good Cut: The diamond offers significant sparkle and brilliance. Does not reflect light back through the table the same as an Excellent or Very Good Cut.
"Cut is the factor that fuels the diamond's fire, sparkle and brilliance"
Diamonds are formed deep within the earth, under extreme heat and pressure. Because of this they often contain either inclusions or blemishes; inclusions are internal characteristics and blemishes are external characteristics. Diamond clarity refers to the absence of these imperfections. Without them the more rare and valuable the gem. Keep an open mind when viewing diamonds that have a lower grading such as an SI1 or SI2, but have a very good or excellent cut. For example, the “eye visible” inclusions that gave the diamond an SI2 grading may be insignificant and the overall appearance still dazzles.
Diamonds receive a Clarity Rating based on a world industry standard scale:
FL : Flawless - No inclusions or blemishes visible using 10x magnification.
IF : Internally Flawless - No inclusions and only blemishes visible using 10x magnification.
VVS1-2: Very Very Slight Inclusions – Inclusions are difficuilt to see using 10x magnification.
VS1-2: Very Slight Inclusions - Inclusions are visible under 10x magnification but characterised as minor.
SI1-2: Eye clean but small inclusions - Inclusions are easy to find using 10x magnification.
I1-3(P1-3): Imperfect - Inclusions are obvious using 10x magnification and generally visible to the naked eye.
"Inclusions in diamonds are normalities not abnormalities."
Most diamonds of gem quality used in jewellery vary in shade from completely colourless down to a visible yellow or brown tint. The colour grading scale starts with the letter "D" and increases with the presence of colour to the letter "Z". Many of these colour distinctions are so subtle, as to be invisible to the untrained eye and each letter grade has a clearly defined range of colour appearance.
A master set of diamonds based on their range of colour is used to grade the diamond.
D : Colourless.
E, F: Virtually colourless.
G, H : Near colourless.
I : Appears Colourless.
J: Very slight colour is visible.
K: Slight colour visible.
L to Z: Colour visible.
"The Colour distinctions are so subtle they are invisible to the untrained eye."
Carat weight is the most objective of the diamond’s characteristics. There are no estimates, comparisons, or judgments. The only requirement is precisely balanced scales capable of measuring extremely small weights.
The weight or size of a diamond is measured in carats (ct.).One carat weighs 1/5 of a gram (5 carats in 1 gram). The term ‘points’ when discussing diamond sizes is 1 carat divided into 100 points, with each point 1/100th of a carat.
1 - 1.00 carat = 100 points
¾ - 0.75 carat = 75 points.
½ - 0.50 carat = 50 points.
¼ - 0.25 carat = 25 points.
It is important to note that diamonds of the same weight don't necessarily have the same size appearance. A diamond which has a deep cut will look smaller than a diamond of the same weight which has a shallow cut.
When diamonds are mined, large gems are discovered much less frequently than small ones, which make large diamonds much more valuable. Diamond prices rise exponentially with carat weight with a 2 carat diamond of a given quality worth more than two 1 carat diamonds of the same quality.
"Weight does not always enhance the value of a diamond"