Cut is perhaps the most crucial of the 4Cs. Cut does not refer to a diamond’s
shape, but rather to the quality of workmanship (proportion and
arrangement of facets) for round brilliant diamonds.* The quality of a
diamond’s cut determines the amount of brilliance, sparkle and fire that a
diamond shows. Grades range from ‘Excellent’ to ‘Poor.’
*Note that fancy cut diamonds such as pear or heart-shaped diamonds do not have GIA cut grades, because there are wider parameters for their proportions and facet arrangements.
Tip: Most diamonds on the market have ‘Excellent’ to ‘Very Good’ cut. Diamonds with a ‘Poor’ cut grade will generally appear lifeless and dull.
Colour measures a diamond’s absence of color. This is because most “colorless” or “white” diamonds actually contain trace amounts of yellow, brown or gray color.
The less color in a diamond, the more desirable and valuable it is. There
are 23 color grades on the D-to-Z scale, with D meaning that a diamond has
no detectable color at all and Z meaning that a diamond has “light” color.
Any diamond beyond the Z color grade is a fancy color diamond and is
evaluated on a different color scale.
Color grade impacts the price of a stone, but differences of one to three color grades are not easily detectable to untrained eyes. Diamonds graders evaluate diamonds face-down in special environments to see subtle color differences.
Tip: D, E and F grade diamonds tend to be extremely rare and valuable. G and H diamonds are typically considered good value. Color becomes more visible in the I grade and below.
Clarity measures the amount, size and placement of internal ‘inclusions’ and external ‘blemishes.’ Inclusions include small crystals or fissures within the
diamond. Blemishes include chips. Grades range from ‘Flawless,’ which
means a diamond has no visible imperfections at 10x magnification, to
‘Included,’ which means a diamond contains a significant number of
imperfections. Diamonds with grades down to VS2 (Very Slightly Included)
or SI1 (Slightly Included) do not typically have eye-visible inclusions.
These diamonds can be good value. Diamonds I1 (Included) or lower have
inclusions that are easily seen and can appear less attractive; some of
these inclusions might also impact the diamond’s durability.
Tip: Brilliant-cut diamonds show clarity characteristics less than step cut diamonds do, because the pattern of the facet arrangement obscures inclusions better. If you want to buy a step cut diamond (such as an emerald cut), you may have to go higher in color and clarity than with a brilliant-cut diamond.
Carat refers to a diamond’s weight. Generally speaking, the higher the carat weight, the larger the diamond appears and the more valuable the stone. How large a diamond appears also depends on its proportions. For example, a
one-carat diamond that is wider but has shallow proportions will appear
larger than a one-carat diamond with excellent proportions.
Tip: Diamond prices go up exponentially as carat weight increases. They increase more at certain “magic sizes,” such as 0.5, 1.0, 1.5, 2.0 carats etc. Buying right below a “magic size,” such as purchasing a 0.95 carat diamond instead of a 1.0 carat diamond, can save money without making much of a difference in visual impact.
Read about Diamond Fluorescence. Click on the Image below
*Courtesy of GIA
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