Light diamond crystals vs dark diamond crystals

By Todd Gray

January 21, 2013

In the first place, the color of diamond crystals is something that can be absolute or relative in appearance. In other words, a crystal may be light or dark in color, or it might just be the lighting. As a matter of fact, the lighting used to illuminate diamonds for clarity photography often makes the clarity characteristics look dark. That is because the light source is positioned behind the diamond and thus the inclusions are being backlit.

As a matter of fact, most diamond clarity photographs are taken using a light source that is positioned directly below the diamond. While the camera is located above the diamond. Since the diamond crystal is located above the light source, it interrupts the light as it passes through the diamond. In this situation, it’s common for inclusions to seem dark even when they are light or translucent in color.

This is why people look dark in sunset photographs on Instagram when the sun is setting behind them. As a matter of fact, the subject will appear dark in that photograph unless a flash is used to offset the effect of the light source being behind the person being photographed.

The Effect of Lighting on Inclusion Appearance:

Sometimes the use of an additional light source positioned to the side or top of the diamond and directed towards the same diamond crystal will result in the inclusion appearing more translucent or lighter in color than it appears with the solitary light source located beneath the diamond.

Light Dark Diamond Crystals

However, sometimes the diamond crystal really is dark in color and no amount of lighting or a difference in the position of the light source will have an effect upon the color of the diamond crystal. Take a look at this 1.09 carat, H-color, SI-1 clarity, James Allen True Hearts diamond for example. The dark crystal that is visible in the middle of the table facet looks to be pretty dark. At the same time, the inclusion is larger and size and easy to see in this clarity photograph.

If you watch the inclusion in the video, you will see that it remains dark from all vantage points. With that in mind, it’s likely that this inclusion is a dark crystal. At the same time, that is not necessarily a bad thing since this photograph was taken at 35x magnification. In other words, it’s not likely that the inclusion will be of any consequence. However, a dark crystal of this magnitude is going to be easier to see than an inclusion that is lighter in color. That does not mean that it will be visible to the naked eye.  You’ll have to ask James Allen about the visibility of the inclusion without magnification.

Are Lighter Diamond Crystals Harder to See?

People often assume that diamond crystals that are lighter in color are more difficult to see within a diamond than inclusions that are darker in color. However, this is not necessarily true.  The size, structure, and location of the diamond crystal will have a direct effect upon the visibility of the inclusion, the color of the diamond crystal is just another characteristic to be considered.

The easiest way to picture this in your mind is to simply consider whether a dark cloud up in the sky is any easier to see than a white cloud. With that in mind, it all depends on the conditions at that particular moment on that particular day because every cloud is different and the lighting conditions will have a definite effect upon your ability to see either cloud, light or dark.

When we look at clouds up in the sky, one of the factors which dictate our ability to see the clouds is contrast. As a matter of fact, this same principle is applicable when trying to locate inclusions within a diamond.  In addition to the position of the light source having an effect upon the color of diamond crystals, the facet structure of the diamond, as well as the size, shape, and location of the inclusions within the larger diamond, will have an effect upon the visibility of the diamond crystals.

Every Diamond Crystal is Unique:

Because each diamond crystal is unique and no two diamond crystals are absolutely identical, each diamond crystal must be evaluated and considered on an individual basis and from a variety of vantage points in order to determine the visibility of the diamond crystal within the diamond being considered.

As a matter of fact, diamond crystal inclusions come in a variety of shapes and sizes. Some are extremely small, the size of a pinpoint and thus are deemed “pinpoints” on the key to symbols on the plotting diagram located on the diamond grading report.  Other diamond crystals are long and thin and thus referred to as a “needle” and others are larger and simply called “crystals” while small clusters of pinpoint size diamond crystals are referred to as clouds.

Diamond grading reports do not provide insight into the relative translucency or “color” of the diamond crystal because of the effect which the light source used to locate the inclusions within a diamond can have in terms of whether the diamond crystal appears to be light or dark.

Does the Color of Inclusions Affect Durability?

I was recently asked whether the color of a diamond crystal has any effect upon the durability of a diamond. As a matter of fact, the color of an inclusion has no effect upon the durability of the diamond, nor the structural effect of the inclusion upon the diamond crystal.  It is simply an identifying clarity characteristic.  The potential for any inclusion to have an effect upon the durability of a diamond is the result of the overall size and nature of the inclusion in terms of the relative position within the diamond, whether it is located near the surface or edge of the diamond and/or effects the integrity of the actual crystal structure of the diamond.

For instance, a “twinning wisp” which is the result of an actual twisting of the crystal structure of the diamond has the potential to present a durability risk because it has a direct effect upon the crystal structure and the cleavage planes within the diamond.  A “knot” which is similar to a knot located within a piece of wood has the potential to present a durability risk to a diamond because it can “pop” out of the stone under the right circumstances… and a cavity which is a hole within the crystal structure poses a similar durability risk to a cavity located within a tooth or any other substance, but all of these inclusion types are not necessarily a durability risk on their own, but require additional factors such as pressure, dramatic changes in temperature and being struck to pose a viable durability risk to the longevity of a diamond.

Todd Gray

About the author

A mad scientist with a passion for improving diamond cut quality to maximize light performance and sparkle factor. I speak geek in degrees of optical precision between bouts of freediving. My ghostwritten ramblings haunt the rabbit holes of information found on many diamond vendor sites. Diamond buyer, author, consultant, errant seeker of deep blue water.

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