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5 Tips for Choosing a Diamond

Diamonds, specifically diamond rings, are among the most popular pieces that we sell in the Fine Jewelry department. Purchased for significant occasions; buyers want the “perfect” stone. The internet is full of information, which can sometimes be overwhelming. Here are the five crucial things to keep in mind when purchasing a diamond.

Art Deco Diamond and Emerald Ring, Grogan, sold for $19,680

1. Color

The diamond color grading scale progresses from D-Z. D-F color diamonds are what we call “colorless,” which means they have the least amount of yellow or brown tones. G-J color diamonds are called “near-colorless,” K-M is “faint,” N-R is “very light,” and S-Z is “light.” Most people that are new to diamonds begin to see the difference at about J/K color. Price can vary widely depending on color. For instance, a 1.00-carat diamond can range from $2,000 to $10,000, with the only difference being color.

2. Clarity

Diamonds form over long periods of time deep under the earth subjected to extreme heat and pressure. The process that creates diamonds results in most stones having small natural birthmarks on the surface or inside. The fewer inclusions or blemishes, the rarer and more highly priced the diamond. The clarity rating system begins with Flawless, then to Internally Flawless, followed by Very Very Slightly Included, Very Slightly Included, Slightly Included, and finally Included. All clarity grading is done under 10x magnification, so most often you will not be able to see any clarity characteristics with the naked eye.

3. Carat weight

Unmounted Diamond sold for: $159,000

We weigh diamonds using carats. This weighing system originates with ancient gem traders that used carob seeds as counterweights in balance scales. Sometimes at auction, you will notice that we use an approximate carat weight. That means we have not taken the stone out of the mounting and have estimated the weight using measurements. When buying a diamond, it is useful to know that there are significant price differences if a stone is over or under a certain amount. For instance, a round, 0.99 cts diamond with F color and VVS1 clarity is worth approximately $4,500 while a diamond with the same grading but a slightly higher weight of 1.01 cts is worth approximately $6,000. Those .02 carats can make a big difference!

4. Cut

The cut refers to the shape of the diamond and the quality of the cut. Round is the most popular shape, and all other shapes are categorized as “fancy” and included marquise, oval, pear, and emerald-cut. Rounds tend to be more expensive than the fancy shapes. A cut grade of the diamond measures how well the diamond is fashioned to ensure the maximum return of light to the viewer’s eye. The proportions are calculated and then ranked from excellent to poor.

Platinum and Diamond Solitaire sold for $189,000

5. Give yourself the freedom to ignore 1-4

I sometimes see clients purchase a diamond based upon the stone’s gemological report without even looking at the stone. At the end of the day, you’re not buying the report; you’re buying the diamond. Make sure that you love it! Many clients prefer the old European-cut diamonds used in pre-1940s jewelry. Those stones seldom get a stellar cut grade, but they have a unique way of reflecting light that draws the eye in. Some very pleasing yellowish diamonds have a low color grade. Have confidence. What you like is more important than anyone else’s opinion.


7 thoughts on “5 Tips for Choosing a Diamond

  1. Hi
    We are looking for a 3 carat ,cushion cut with 2 triangle side diamonds. I am a dealer and willing to spend $30,000.00
    Thank You,
    Deborah Auer

    • Hello Deborah, You may be interested in our lot alert feature. Lot Alert will automatically send you an email when items that match your keywords are coming up for auction. The email will contain a link directly to the online lot listing for each matching item. You do not need to create an account with Skinner to sign up for Lot Alert.

      To sign up for Lot Alert, visit this link:


  2. Thanks for all this great information about buying a diamond! One thing that I really like is that you say to look at the weight of the diamond using Carats. it would be nice to know that you will be able to get a quality diamond in the end.

    • 1 carat equals 200mg
      Simply weigh the stone, divide mg wt by 200 = carats total weight
      Remember, just the stone, no ring or mounting!

  3. There is a lot to look for when you’re choosing a diamond and I do like that the article brings up cut. After all, you will want to make sure that it has the right shape to match your design. Of course, if it doesn’t then you might be able to find a diamond cutter to shape it for your needs.

    • Thanks for the question! Colored diamonds are rarer than near colorless and colorless diamonds, but blue diamonds are certainly among the rarest.

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