Because it is composed of a generally transparent material, diamond lets light pass through it, even in its most rough condition. But early on in history, stone cutters realized that you can get extra sparkle if you facet the diamond, and they set about finding out the best combination of facet size and shape and angle to get the most sparkle. Eventually, one design with 58 facets was shown to be the most efficient way to maximize the stone’s best qualities and this became known as the ideal cut. It remains the industry standard, and is the shape that most people recognize as being a diamond shape.
This does not mean that diamonds of the same size are equal when it comes to cut. A lot depends on the skill of the diamond cutter as even the slightest variance in the angle of a single facet or its size or its effect on the symmetry of the stone will affect its value. Diamond cutting is part art but within the confines of exacting scientific boundaries.
This does not mean, however, that the diamonds that are cut to an ideal shape are automatically the best. Not at all. Part of he job of a highly skilled cutter is to determine what shape will be the best one to create the largest possible polished diamond from a given piece of rough. And rough diamonds come in all kinds of shapes. So a pear- or emerald-shaped diamond has as much claim to being perfect as the ideal cut, particularly if it produced a larger stone. In fact, most of the world’s biggest, most famous diamonds are not ideal cuts because the chief goal was to maximize their size.
It may surprise some people to learn that diamonds have color since many people know diamonds only as cut gemstones that are as clear as optical glass. But the truth is that the bulk of the diamonds on sale have a tinge of color ranging from the barest hint of a color to a strong hue. Like diamond cutting, determining the color of a diamond is a precise process and it affects the value of the stone.
Color in diamonds comes from chemical impurities in the stone and imperfections in its molecular structure. The variety of impurities that can be found is large enough to give the stone a potential array of colors, the predominant ones being yellow and brown.
This color is considered normal and does not mark a stone as immediately inferior to another. Diamonds with the most intense colors are referred to as “fancy color” diamonds and have names like cognac or champagne diamonds. In fact, the ones with the most extreme amount of color are rarer than those that are absolutely clear. A canary yellow diamond, for example, is a more prized possession for some people – and more expensive – than a comparably-sized clear diamond because it is rarer.
This does not mean that diamonds that are absolutely free of impurities and imperfections are commonplace. Quite the opposite. Crystal-clear diamonds are valuable and sought-after because of their rarity as well as their beauty. The stones between these two extremes are graded on the scale shown here.
Absolutely colorless. This is the highest color grade and quite rare.
Near to colorless. These may appear colorless when mounted in white gold or platinum.
Diamonds in this category have a visible yellow or brownish tinge. These diamonds are not generally recommended for engagement rings and where large-sized stones are appropriate.
Clarity, as the name implies, refers to how clear the material is that the stone is made of, and what surface imperfections it may have. These have a direct effect on how light passes into a diamond and bounces around within it before finally exiting.
The internal flaws are called inclusions and they appear for several reasons, usually either foreign material within the diamond or even another diamond crystal inside it or an imperfection such as a tiny crack in the structure of the material itself.
Surface imperfections are popularly called blemishes and they can be either major or minor and will affect the value of the stone accordingly.
Clarity is determined by the number, size, color, location, orientation and visibility of the inclusions and blemishes as seen under a 10X magnification. As mentioned earlier, flawless stones are very rare, so it is likely that you will be considering stones that are less than perfect. That’s perfectly fine, particularly as many of these imperfections are scarcely visible to the naked eye and often only when you are scrutinizing the diamond very closely.
Here is a chart showing how diamonds are graded for clarity.
No flaws internally or externally.
No flaws internally. This category of diamonds is also very rare and valued highly.
Very, Very Slightly Included: Very difficult to see inclusions under 10x magnification. These diamonds are high quality.
Very Slightly Included: Inclusions are not visible to the naked eye. This category is less expensive than the VVS1 or VVS2 grades.
Slightly Included: Inclusions are visible under 10x magnification. This level of clarity is considered by many to be the best value buy because the inclusions are not visible to the naked eye. The prices for these diamonds are notably lower compared to those in clearer categories.
Slightly Included-EGL: This is a category of clarity that is promoted by and is not certified by the Gemological Institute of America or other gemological institutions. Diamonds in this category are likely to be graded by GIA as either SI2 or I1. EGL distinguishes these diamonds as having no black inclusions or cracks that are visible to the naked eye, but they may posess some very minor white inclusions which are visible to the naked eye.
Included: an I1 clarity diamond will have a visible flaw which can be seen with the unaided eye. If your budget is limited and you can only afford diamonds in the SI3 or I1 clarity, be sure to examine them under 10X magnification yourself before making the purchase. It will help you decide which one to buy. Any reputable jeweler would be happy to show you how to use a magnifier.
Included: The inclusions in this category of diamonds will be visible to the naked eye. They will have many black spots from the black inclusions and may appear cloudy from the white inclusions and cracks.
Diamond Carat Weight
The size of the diamond is called its carat weight and actually refers to its mass. All other characteristics being equal, the carat weight is the biggest determinant of the price of a stone.
A one carat diamond ring will always cost more than a ring made of smaller diamonds that weighs the same or even more.
Generally, once you have decided on which cut, color and clarity you want, the next important decision is to decide on the carat weight. The chart below exemplifies how different carat weight looks after it is set in a ring.
Tips to help you determine the right carat weight
Some considerations you will have to keep in mind: the size of the recipient’s finger, any personal preferences, the type of setting and the most important factor, the budget. Try looking at the purchase in the following order.
First, decide on to your budget and then explore the various qualities and designs available in that price range.
Factor in the shape of the finger. If the fingers are long, a small carat diamond may look even smaller and vice versa.
Be sure to match the setting of the diamond ring with the carat size. For example, a wide band can make a stone look smaller than it might with a narrower band. Keep in mind the word “misfit” when matching diamonds with settings and use your own judgement. Here’s one more thought regarding setting: choose a setting that gives maximum protection to the diamond.
The lifestyle of the person is also something to keep in mind. Someone who is very active will potentially subject a diamond ring to more knocks and scratches than a more sedentary person, particularly if the setting makes the stone stick out a lot.
Perhaps the only immeasurable consideration is personal preference. That’s because many people don’t have any regarding diamonds – “any diamond is a good diamond” – and it can be difficult to find them out without letting the person know you are shopping for one. But if someone says that she really likes champagne diamonds because they really look nice with her skin tone, then that should be a good indicator of how to proceed.