Diamond Buying Guide

You are thinking of finally getting into the luxurious world of diamonds, but how do you choose the perfect diamond ring or pair of diamond earrings? Fear no more, we've got all the information you need to make sure you're getting the most out of your diamond purchase.

The 4 Cs: Cut, Color, Clarity, and Carat


Many of you have probably heard of the 4 Cs and possess a basic knowledge of their importance to diamond grading. For those of you who haven't heard of the 4 Cs, or those of you looking for a refresher, look no further.


The cut of any diamond has three attributes:

  1. Brilliance: the total light reflected from a diamond
  2. Fire: the dispersion of light into the colors of the spectrum
  3. Scintillation: the pattern of light and dark areas and the flashes of light, or sparkle, when a diamond is moved


These three attributes are what gives diamonds most of their visible appeal. The cut is responsible for making the light reflecting in the diamond look like it's dancing with your finger's movements. When looking for the perfect diamond, you want to be very aware of how well the diamond was cut.

Unfortunately, the cut is the most difficult for a consumer to grade objectively. So, let's simplify it; cut refers to the way light enters and exits the diamond.

In a well-cut diamond, light enters and exits through the top, absorbing light and shooting it back out of its many facets. This is what gives well-cut diamonds their sparkle that is so sought after. The more the diamond sparkles, the more likely the diamond is to have a high cut grade.

According to the GIA (Gemological Institute of America), cut grades are rated as ideal, excellent, very good, good, fair, and poor. If you're still not sure your eyes will be able to tell the difference between an ideal cut diamond and a poorly cut diamond, then ask your salesperson what the grade is. Or you can explore here.


Diamonds are typically valued by how closely they approach colorlessness - the less color, the higher their value (the exception is fancy color diamonds, which we won't get into in this post). Most diamonds found in jewelry stores run from colorless to near-colorless. Near-colorless contains slight hints of yellow or brown. Small differences in diamond color can make a very big difference in diamond quality and price.

Here's how the GIA grades color:

Buyers who are looking for a white diamond search for anything ranging from D to J. When you start getting to the K to N range, you'll hear some salespeople refer to the diamond as having "warmth", meaning it's starting to show some yellowish hues.

If you are a potential shopper searching for a colorless engagement ring, you'll likely find that any diamond in the D to J range is acceptable.


Because diamonds formed deep within the earth, they often contain unique birthmarks, either internal (inclusions) or external (blemishes).

Diamond clarity refers to the absence of these inclusions and blemishes. Diamonds without these birthmarks are rare, and rarity affects a diamond's value. Again, the GIA created a scale to make it easy to understand clarity grading:

Flawless/Internally Flawless: these diamonds are very rare to come across and will be expensive. They are sometimes referred to as "museum quality" or "investment grade". If you have the ability to buy a flawless diamond, you should not pass it up.

Very Very Slightly Included: inclusions that are invisible to the eye. These diamonds appear identical to the higher grades when viewed with the naked eye.

Very Slightly Included: possessing very little inclusions, these diamonds are still very high quality and more accessible to the average consumer. Around 1 in 100 untrained observers would be able to detect inclusions with the naked eye.

Slightly Included: SI1 is usually the lowest grade a diamond can be while still having inclusions being invisible to most naked eyes. SI2 is where one will begin to notice small inclusions with their naked eye. Either way, the clarity grading of these diamonds can be used for a budgetary purchases.

Included: these diamonds have inclusions that are visible by the naked eye, sometimes even being so included that it affects the diamond's durability. If you're looking for a diamond to be proud of, stay away from these.


Carat is the term that almost everyone knows, but it's also a very misunderstood aspect of the 4 Cs. A carat is a unit of weight equal to 0.20 grams. While carat weight is important, customers should also care about the overall shimmer of their diamonds.

All else being equal, as carat weight increases so does the price of the diamond, because larger diamonds are more rare and more desirable. However, prices begin to fluctuate when there is differences in clarity, color, and cut of a diamond.

Most shoppers think that carat size is the be-all and end-all of diamond quality. This is simply not true. While size may be important to some shoppers, the other 3 Cs add plenty of value and beauty to a diamond. You can buy a big diamond with poor cut, clarity, and color for the same price as a smaller diamond with high grades in cut, clarity, and color. However, that big diamond won't be as attractive as the smaller stone. Don't be sold on big sizes with poor cuts; bigger is not always better.

5th C: Certification

So you know the basics, you go out and find a diamond that looks great, but how can you be sure the jewelers aren't lying to you about the diamond's scores? This is when you ask if it comes with a certification!

Diamond certifications are done by reputable laboratories to ensure that an impartial judgement is made. Each diamond certificate issued is uniquely numbered, and corresponds to one individual diamond. From that point forward, the diamond and certificate will travel together from seller to buyer.

Certified dealers, like Gunderson's, only carry diamonds that come with a certification to help give assurance to their customers. We suggest that you protect your self by guaranteeing one of the biggest purchases you make is certifiably graded.


You've done your research. Now go out and enjoy the luxurious life of being a diamond owner.

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