Contrast is one of the most important contributing factors to our perception of brightness and sparkle within a diamond, and yet it is a topic which is rarely discussed because the majority of diamonds exhibit very little contrast as a result of being cut to lower standards of diamond cut quality.
The 0.95 carat, G-color, VS-1 clarity, round from High Performance Diamonds which is pictured to the left displays an excellent degree of contrast. That will make the diamond appear brighter and to exhibit more sparkle in a wider variety of lighting circumstances than a diamond which exhibits a lesser degree of contrast. For instance, this diamond will look spectacular when viewed in fluorescent lighting…
However, the vast majority of diamonds look dull and lifeless when viewed under the type of fluorescent lighting that is used to illuminate most offices and workplaces, because fluorescent lighting lacks ultra violet which is a critical contributing factor to diamond sparkle. High contrast diamonds tend to look incredible in practically all lighting environments, including those where other diamonds tend to flatten out in appearance due to being starved for light.
High Contrast in Diamonds enables us to see depth:
Contrast is a factor of sight that increases our ability to see depth, not only in diamonds but also in situations like the stage curtains and the black and white tile floor which is pictured to the left.
Without a sufficient amount of contrast, the text would not be clearly visible on the image, the curtains would seem dull and lack theatrical presence, and the tile floor would appear to be flat and without depth to draw our eyes on to the stage. Likewise, a diamond without contrast appears to be dull and lifeless, practically devoid of sparkle.
High Contrast is Equally Important in Fancy Shape Diamonds:
Strong levels of contrast is as important for fancy shape diamonds like this 1.088 carat, F-color, SI-1 clarity, Brian Gavin Signature Cushion cut diamond, as it is for round brilliant cut diamonds. Notice how the contrast between the arrows pattern created by the pavilion main facets and other sections of the diamond create the illusion of sparkle as the diamond rotates in this video. High levels of contrast in diamonds is created by combining a very narrow range of proportions, with consistency of facet shape, size and alignment. One way to judge contrast online is through the use of diamond clarity photographs and video like this.
However it can be difficult to accurately judge the degree of contrast within a diamond while it is in motion and contrast levels can be adjusted easily in photographs using practically any photo editing program. Thus in addition to clarity photographs and video, I like to be able to evaluate the diamond using standard reflector scopes images, like those provided on the diamond details pages of both Brian Gavin Diamonds and High Performance Diamonds. Both vendors provide ASET Scope and Ideal Scope images for the diamonds in their inventory, which maks it extremely easy for me to determine the degree and consistency of contrast exhibited by the diamonds which they offer.
In addition, the majority of diamonds offered by both vendors are graded by the American Gem Society Laboratory (AGSL) on their proprietary Light Performance grading platform which uses Angular Spectrum Evaluation Technology (ASET) to grade diamonds for brightness, light return and contrast… so I can simply look at the ASET image provided on the diamond grading report and quickly ascertain how bright the diamond appears, how symmetrical the pattern of light return is, and how much contrast is being exhibited by the diamond.
Examples of Degrees of High Contrast in Round Diamonds:
I wanted to provide you with an example of how the proportions of a round diamond, combined with varying degrees of optical symmetry have a direct impact upon the degree of contrast, so I conducted a search for round ideal cut diamonds on James Allen because the layout of their diamond search results provides a perfect example to demonstrate what I’m talking about:
As you can plainly see, although all of the diamonds pictured above are represented by James Allen as being “ideal cut” they exhibit different degrees of contrast between the arrows pattern and the other sections of the diamond. Notice how some of the arrow shafts and arrow heads are less prominent in some of the diamonds while they appear crisp and more evenly shadowed in others… this variance is created by what I consider to be less desirable combinations of crown and pavilion angles, and irregularities in the indexing of the facets.
While the high resolution videos provided on the diamond details pages of James Allen make it possible to eliminate such diamonds from the list of diamonds being considered, this type of information is not provided by the majority of online diamond dealers and contrast is rarely discussed at the sales counters of most jewelry stores either… however as you can plainly see, it is an important characteristic of diamond cut quality to be aware of and to take into consideration when buying a diamond.