How to Judge a Diamond's Quality

When begin to search for a perfect diamond, We will certainly find that there is a big difference in price, and price is usually based on assessing the quality of the four Cs of diamonds, including cut, clarity, color, and carat.

Before we make a diamond purchase, we need to familiarize yourself with these terms, and we also need to find a reputable jewelry. Although we can examine the diamond yourself, we can ensure that we get value for the price only if we rely on the expertise of a specialist diamond.

Judging Cut
One of the most important factors in judging diamond quality is judging the cut of a diamond. It’s important because a quality cut diamond will be more brilliant and reflects light more beautifully, and yet the cut of a diamond has the least impact on the overall price of the diamond.

When judging diamond quality on the cut of a diamond, look at the stone in a well lit area. If the light seems to go into the stone and bounce back, showing a sparkling reflective surface, the diamond has a good cut. The angles and shapes of a diamond are important to judging diamond quality and the overall appearance of your diamond.

Not the shape of the stone, cut refers to how well a diamond’s facets are proportioned and aligned to maximize brilliance. According to Tiffany, an excellent diamond cut might sacrifice as much as 62 percent of a stone’s total weight.

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Judging Color
Most diamonds are considered to be ideal if they are transparent, or colorless. Diamonds that are rated as colorless are the most expensive of diamonds.

There are two main ways that jewelers’ use when judging diamond quality based on color. They may pull out a set of reference stones, and find the closest match between the diamond and the reference stone to determine its letter grade. Alternatively, the jeweler may use a colorimeter, which can electronically measure the color of the stone and determine its grade within 1/3 of a grade.

When rating the color of a diamond, jewelers commonly use the letters D through Z. The more yellow or brown tint a diamond has, the less value it receives. The rating D represents a diamond that is colorless; while the rating Z has a yellow or light brown hue.

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Judging Clarity
The clarity of a diamond refers to whether or not the diamond is clear all the way through, or whether it has tiny flaws and cloudy areas within the gemstone. It’s actually very rare to have a diamond with absolute perfect clarity and no flaws, but most diamond flaws are not visible to the naked eye and can only be seen with a magnifying device.

The Gemological Institute of America (GIA) uses a magnification of about 10x when judging diamond quality based on the clarity. There are treatments available to make a diamond appear nicer than it actually is, and the treatments should lower the overall price of the diamond so it is important to do your research before purchasing a diamond to be sure you are not spending more money than you should.

Judging Carat Weight
Carat is the term we used to describe the weight of a diamond gemstone. One carat is equivalent to 200 milligrams of weight. A single diamond with a high amount of carat weight is more expensive than the equivalent amount of carats in multiple stones. This is because finding the larger diamonds is much more rare of an occurrence.

So if you want a 2-carat diamond ring, for example, you may decide to go with a half-carat diamond surrounded by smaller diamonds that add up to one and a half carats to give you the total of 2 carats! Judging diamond quality by the amount of carats is difficult, since different shaped gemstones, and stones with different levels of clarity will be priced differently even if they have the same amount of carats.

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Diamond Carat - What is Diamond Carat Weight?

Diamond Carat - What is Diamond Carat Weight?

When shopping for a diamond, you've no doubt heard references to the 4 C's of diamonds. Diamond carat is one of those popular ”c's” to consider when evaluating a diamond, and it's a term used to describe how much the diamond weighs. A single diamond carat is equal to the weight of 200 milligrams, or .2 grams.

Diamonds are described two different ways in regards to the diamond carat. An abbreviation of “ct” is used to describe the weight of a single diamond stone while an abbreviation of “ct TW” is used when describing the total weight of an entire piece of jewelry- when it has more than one stone in place.

It's important to recognize that two stones may have the exact same carats, meaning they have the same weight measurement, and yet they are completely different in size and appearance. This is due to the actual density of the gemstone. The more dense a stone is, the more weight they have, and sometimes a smaller stone will actually weigh more than a larger stone because of density.

When selecting your diamond ring, you can choose between a single, solitaire style setting (a single diamond on the ring) and a setting that has multiple, smaller stones to make up the ring. The value of a solitaire one diamond carat will actually be more than if you buy a ring that has two diamonds that add up to one carat or greater. Larger sized diamonds are more rarely found when mining diamonds, making them more valuable and expensive than purchasing the same amount of diamond carats in smaller stones.

So how do you determine what size diamond to buy? Do you want a diamond carat of 1, or 2, or do you want a ring with multiple, smaller stones? The answer to this will depend greatly on your budget, as well as the person who will be wearing the ring.

A diamond will look larger on a slender finger, so keep that in mind if the recipient of the ring has thin hands. The actual diamond carat measurement is probably not as much of a concern as the appearance, shape, and setting of the ring. Particularly because a 1 carat diamond ring will not look half the size of a 2 diamond carat ring, it's far more important to select a ring that is pleasing to look at than it is to buy one with the most carats you can afford.

Determine how much money you have to spend, and then decide on the cut of the diamond. Once you have these two pieces of information narrowed down, you can start browsing the diamonds in your price range, in the style you want, and find out what diamond carat you are in the market to buy.

Blue Heart Diamond

Photo by Chip Clark

There is a spectacular diamond in the Smithsonian Collection called the Blue Heart Diamond. Fans of the movie Titanic might think the “Heart of the Ocean Diamond” was based on this stone, and it may have been! However, this diamond hasn’t been cast in the ocean, but is safe and sound at the Smithsonian!

It has also been called the Eugenie Blue Diamond, although it’s uncertain that the Empress Eugenie ever owned this particular stone. It was cut in Paris between 1909 and 1910, but the stone’s origin – Africa or India – is unclear.

It is an enormous heart-shaped, blue diamond weighing 30.82 carats. Its current setting is in a platinum ring, surrounded by white diamonds. It changed hands among famous jewelers – such as Cartier and Van Cleef & Arpels - and owners until it was bought by Harry Winston in 1959 who mounted the diamond in its current ring setting. Winston sold the ring to Marjorie Merriweather Post. Mrs. Post donated the ring to the Smithsonian and it remains there with other famous blue diamonds, including the Hope Diamond and the Heart of Eternity Diamond.

These famous blue diamonds have recently gone through a grading and examination process, to classify their colors and to determine the source of the color. The Hope Diamond is classified as Fancy Deep Grayish-Blue. The Heart of Eternity has been classified as a Fancy Vivid Blue. The Blue Heart Diamond has not yet been classified, but some experts categorize it as either Fancy Vivid Blue or Fancy Deep Blue. Blue diamonds are of particular interest to scientists not only because of the color and the impurities that create it, but because blue diamonds also have an electric conductive property that makes them unique among clear and other colored diamonds.

Diamond cutting styles and variant

Our love of diamonds and admiration of their fire and brilliance has given rise to many different cuts of diamonds. While we still see some of the earliest styles of diamond cuts – such as the round and emerald-cut, there are many more cuts today, some of them patented by their designers and costing hundreds of thousands of dollars.

The most popular cut for a diamond ring today is still the round, brilliant cut. It was developed in the 17th century in Venice. It is still preferred when the raw crystal is in an octahedron formation. Even though as much as 50% of the stone is cut away in the process, often two stones can be carved from an octahedron. More unusually-shaped stones are used for fancy cuts, such as a marquise, pear or heart-shaped diamond. The earliest brilliants had 17 facets on the top of the stone and were called double-cut. This was soon improved with stones cut with 33 facets and were called triple-cut brilliants.

In the 19th century, with the development of better gem-cutting tools, more innovations in diamond cutting styles were developed. In 1919, Marcel Tolkowsky combined the art of cutting with the science of light and refraction and published his book, Diamond Design. These relatively recent geometric calculations were the forerunner of much of diamond cutting work today and led to other, more precise mathematical models engineered to enhance the fire and brilliance of diamonds.

There are now cuts such as the princess cut, trillions, ovals, pear and heart-shaped. Some innovative cutters have even fashioned star or butterfly-shaped diamonds! One patented cut, the Ashoka diamond, is an oblong cut with rounded, brilliant ends, and requires a stone 3 carats or larger. It’s an exceptionally beautiful (and pricey!) diamond shape. Tiffany has also patented a cut of diamond called the Lucida cut. It’s the lucky bride whose fiancé gives her one of these highly coveted stones!

Choosing The Cut of A Diamond

There are many different cuts of diamonds to choose from. The cut essentially refers to the shape that the diamond is cut into – unless you are in the diamond or jewelry business, but this shape has a great impact on the much the diamond sparkles.

The most popular cuts are heart, marquise, oval, pear, princess, round, trillion, and emerald cuts. The shape has an impact on how much the diamond sparkles, but the

actual cutting itself – when the diamond cutter actually cuts the diamond into a particular shape – also matters a great deal. If the diamond is poorly cut, it will lose its sparkle.

However, in the diamond industry, the cut of a diamond doesn’t refer to its shape at all. Instead, this is a reference to the stone’s depth, width, brilliance, durability, clarity, and other aspects of the diamond. Common cutting problems include a missing or off center culet, misalignment, a diamond that is too thick or too thin, cracks, or broken culets.

When shopping for a diamond, you should of course choose the shape that you like the best, but then look at several different diamonds of that shape to find the one with the best cut – the one that sparkles the most, in all types of lighting.

The cut of the diamond determines its shape. There are many different shapes for diamonds. What gives diamonds its brilliance is its facets. Each flat surface you see on a diamond is called a facet. These allow light to enter the diamond where it refracts into a rainbow of colors reflecting against other facets until the light comes out another facet. A diamond cut ideally will reflect the light towards your eyes as shown in the example.

As the image shows, an ideal cut diamond is more effective at reflecting the light back at the viewer. The less-than-ideal cuts lose the light either through the side of the bottom.