Just how important is a diamonds cut quality?

Note this picture above which was taken under 5800 degree kelvin l.e.d's (this would be considered a strong direct light source).  Note the light exiting at various intensities, colors and the sizes of the flashes.  This is a diamond that is typically described as one with great broad flash with a nice mix of pin flash.  Each of the 57 facets are cut to certain measurements and angles that produces this beautiful optical phenomena.  These measurements are referred to on diamond reports as the proportions and getting the right combo's will make for the most absolutely beautiful diamonds. When it comes to the 4C's of diamonds, CUT IS ABSOUTELY KING.  Superior cut will make a K color more beautiful than a D.  It will make an I1 clarity more beautiful than FL.  Understanding cut requires a little more brainwork than the other 3C's but once you grasp it, the end of your journey in research will pay off for you because we're going to show you how to identify the most rare and beautiful diamonds available.

How many web sites or jewelry stores have you visited, THAT DO teach about cut actually show you how well the stone you're considering purchasing is cut? There are sites here on the net that have this little picture of what an "Ideal Cut" is.  There are also sites that define an Ideal Cut in different ways and don't even consider pavilion depth/angles and crown height/angles but only "total depth and table" when it comes to the proportions.

With all the Web sites selling diamonds and have huge lists of diamonds they have in stock, how many actually tell you what these dimensions are? At best, if the diamond is accompanied by an old GIA lab report you'll at least get the table percentage, total depth percentage, girdle and culet size. Is this information specific enough to tell you about the proportions? How important is it for you to know what the pavilion and crown information  or upper girdle, lower girdle and star facets are and how does it affect the brilliance? IT IS VERY IMPORTANT!  This is probably the most important part of this site you're going to hit, so make sure you absorb what you're going to learn in this section, because the proportions can either make or break a stone and can affect the value by up to 40%. That's a lot of money.  Take your time to go through this section here on proportions, because this one factor can affect the value in the diamond by up to 40%.

How a Diamond Handles Light

There are 2 different types of light that can emanate from a diamond.  One is called brightness and the other fire. The brightness is the return of white light to the human eye, the fire is the return of colored light to the human eye.  These are not subjective terms, but can be scientifically defined and examined.  The movement of both white and colored light within the diamond as it is moved before the observer is properly called scintillation.  When a diamond has good brightness and fire, it's scintillation will also usually be very good as well.

Suppose the same amount of light should fall on a pile of black carbon powder as on a cut diamond. Both are formed from the same chemical, but clearly they will handle that light in quite different ways.

Most of the light which falls on the powder is absorbed, which is why it appears black. But when light strikes a diamond, a portion of the ray is reflected from the surface. This is called external reflection. Since the table facet is the largest facet on the diamond and is directly on top, the size of the table is going to directly affect external reflection. This, in part is the white light people observe as they look at a diamond. If the table facet is too big or too small you are going to get an unbalanced display of reflected light and dispersed light. An acceptable table size that falls at about 53-60% of the diameter of the diamond will give you a balanced display of both white and spectral light, as long as the diamond has a proper balance of crown & pavilion angles and girdle facet cutting. Read on to learn more.

Here's a live picture I caught digitally of a good example of external reflections of white light off of facet surfaces combined with white light reflecting from the interior. The diamond on the left has white light reflecting from above off of a kite (bezel) and star facet. The diamond on the right, the kite and one of the upper girdle facets.  You can also easily observe white light reflecting off of the facets internally as well.

The other part of the ray enters the diamond and, as it does so, it bends due to the greater optical density of a diamond. This is called REFRACTION. The light is then reflected from the internal surfaces of the diamond - which is called internal reflection.

The bottom portion of the diamond, called the pavilion, has direct bearing on the internal reflections and the light that is refracted through the diamond. If the pavilion angles are not cut to the proper angles and combined with the proper crown angles, the light will not have the internal reflection that is displayed in the above diagram. When pavilion angles fall too deep or too shallow, this is what results.

 
On the left is an example of diamond that tend to look bigger than what they weigh, but see that solid beam of light falling out the bottom of the stone? That's because of a shallow pavilion. All that light that's leaking out the bottom is light that should be hitting someone in the eye... LIKE YOUR GIRL! Part of the internal light is reflecting out of the opposite side, but you are still not getting max brilliance. Understand?

Here is a representation of a diamond that would  have pavilion angles greater that are considered too steep. Notice how all internal refracted light reflects off one side of the pavilion only to escape out the bottom of the other side. THIS TOO IS BOGUS!

Now here's what happens to internal refracted light when the pavilion angles are coupled with the proper crown angles.

BINGO!!!   Do you now understand the importance of proper proportions??? I hope so because this one factor can make or break a diamond.  All refracted light is reflected off those pavilion facets and BANG, that baby talks!!! Question: How do you know you are getting a diamond with the right crown & pavilion angles to ensure your diamond will handle the light properly like this?   Here at Good Old Gold's Ultimate Diamond Info Site, there is no guess work involved. Once you proceed and learn how the proportions are measured and how light is examined, you'll see how you can know exactly what the proportions are and the light performance on the diamond you'll purchase. This is one unique feature we offer here on the "UDIS".  Let's finish this off though and learn what happens to this refracted light once we know the pavilion is righteous!

The ray then emerges from the top of the diamond where, once again, it is bent or refracted and is separated into the colors of the spectrum. It is this dispersion that gives the diamond it's fire. The part of the diamond that is directly responsible for the amount of dispersion you're going to see, is the crown facets and the crown angles.  A diamond that is cut to GIA's top standards will exhibit a superior amount of brightness, fire & scintillation back to the observer.  We know because we've tested many stones already that fall within the proportion combinations that produce a GIA Excellent Cut Grade.

Now this wasn't too hard to understand now was it?

These next few pictures are taken of super ideal cuts that are typical of the quality of diamond we feature here on "The Ultimate Diamond Information Site".  These are the rarest and most beautiful cut qualities in the world and exhibit the most fire and dispersion that is possible to get in a diamond and a very good example to show you what is meant by dispersion. 

Look at the colors coming off of that huh?  Look at the pinks, blues, yellows, violets ...  Is cut quality important?  If you want your diamond to really glimmer YOU BETTER be insistent about cut quality.  While I have these other graphics and instruments to demonstrate the importance of cut ... the above pictures say it all.

The TOTAL BRILLIANCE of the diamond depends on the amount of internal and external reflections of light from the diamond to the eye.