How to Buy a Diamond

If you're wondering how to buy a diamond, one of the first steps is familiarizing yourself with the four Cs, which are cut, color, clarity and carat weight. Understanding the four Cs can enable you to make appropriate trade-offs if you are on a budget, and it can help you avoid overpaying for a diamond as well. Below is a diamond buying guide that covers what to look for and ways you may be able to save money on your purchase.


The Four Cs

1) Cut

The cut of a diamond refers to its shape and the quality of the cut, including the proportions, symmetry and polish of the diamond. A diamond's cut determines how light is reflected, and factors in the quality of a cut are the smoothness of the diamond's surface, the symmetry of the cut and the sizes and angles of the diamond's facets.

  • While the cut is considered to be the most important factor in the beauty of a diamond, there is not a set standard for rating the quality of cuts because the Gemological Institute of America, or GIA, has not set one. Therefore, what one jeweler labels an excellent cut may only be rated as a good cut by another.
  • In a diamond buying guide, you are likely to see cut listed as the most important of the four Cs. This is because an excellent cut can make an inferior diamond appear to be of higher quality, but a poor cut can make a diamond with exceptional clarity and color appear dull.
diamond cuts
2) Color

In general, diamonds that have little to no color are the most sought after. The GIA has a rating scale that goes from D to Z, with D being a diamond that is completely lacking in color.

  • Diamonds with colors that go beyond the rating of Z are considered fancy color diamonds, and if the color is rare, they may be more valuable than colorless stones.
  • The majority of people, including experts, cannot tell the difference between diamonds with color grades that are one step above or below each other unless the gems are side by side. Even then, diamonds with I ratings and above may be difficult to tell apart when next to each other.
  • Color is hard to determine when a diamond has been set in a ring, and smaller diamonds are also harder to detect color in.
  • If you are looking for a highly colorless diamond, consider a fluorescent diamond since they sell for about five to 15 percent less than those without fluorescence. Faint to medium fluorescence is not visible to the naked eye, so there's no reason to not take advantage of the discount.
diamond color
3) Clarity

All diamonds have tiny imperfections in them, and the fewer the imperfections, the greater the diamond's clarity. Internal irregularities are considered inclusions, and external markings are blemishes.

  • The GIA has five main grades of clarity, which are Flawless, Internally Flawless, Very, Very Small Inclusions, Very Small Inclusions, Small Inclusions and Imperfect.
  • About half of all diamonds are rated as having very, very small inclusions, and their imperfections are invisible to the naked eye. These diamonds are a fraction of the price of diamonds that have flawless ratings.
  • It is harder to see imperfections in smaller diamonds, so clarity is more of a concern with diamonds that are less than two carats in size.
diamond clarity
4) Carat Weight

Diamond weight is measured in carats, and carats are divided into 100 points. A 100 point diamond is a one carat diamond, and a 50 point diamond is a half carat diamond. Since carats are a measurement of weight, two one carat diamonds may be different sizes.

  • Diamonds that are just slightly smaller than popular sizes generally sell for less but appear to be the same size. For example, a .90 carat diamond will appear to be a full carat but may cost significantly less.
  • Total carat weight is the weight of all of the diamonds in a ring or a piece of jewelry.
diamond carat


Insuring A Diamond

Along with knowing how to buy a diamond, it's also important to protect your investment. Although you are likely to have some form of guarantee from a jeweler, it generally will not cover theft or loss, so it's a good idea to consider an insurance policy for your jewelry. If you have homeowner's insurance, your jewelry may already be covered, but there may be a deductible.

  • Should you decide to insure your jewelry, make sure your policy provides full replacement coverage, not just a percent of the value of the item in question.
  • Determine the process for having an item replaced and if you have to obtain a replacement from a specific retailer or company.
  • Find out if there are any circumstances where your diamond would not be replaced.