TUE - FRI 11:30 AM - 6.00 PM, SAT 11:30 AM - 5:30 PM (Appointments Recommended)

MSD Company LogoMSD Company Title

Know Diamond 4Cs

Dino LonzanoLast updated February 09, 2024, 11:43 AM

When you are in the market for a diamond, you want to make sure that you are preparing yourself with the right amount of knowledge and to make such a purchase that will be both beautiful and full of value. There are Four C’s to pay attention to when you are purchasing a diamond. Diamond shopping should not be stressful. It should be very organic and fun. Knowing the four Cs will give you the confidence in properly selecting the perfect diamond to place on her finger.

Pear-shaped blue diamond ring
Diamond cut grades are measured using two universally accepted grading systems:
1. GIA Grading System (Gemological Institute of America)
2. AGS Grading System (American Gem Society)


No matter the shape of the diamond, you want it to be properly proportioned.

The Cut grade of a diamond determines the brilliance and scintillation a diamond possesses. You want to be able to see the diamond sparkle, whether in natural sun, room lighting, or at dinner.

Remember, the shape of the diamond (round, heart/oval/marquise, pear, etc.) does not refer to the cut. You can have any shape of a diamond excellently cut or poorly cut.

There are two universally accepted diamond-cut grading systems: GIA System and AGS System.

Ask to view the diamond in different light settings.

You can compare the value with the grading chart (Figure 1). Closer the diamond cut grade gets to “Ideal” or “excellent”, higher the brilliance.

Brilliance of a diamond comes in three forms:
1. Brightness:Refers to the amount of white light reflected from the inside and outer surfaces of the diamonds.
2. Fire:Refers to the rainbow-colored light coming out of the diamond.
3. Scintillation:Refers to the sparkles you see when you tilt or rotate the diamond.


Color of a diamond is the second most important quality that contributes to its beauty. In fact, the word “color” is used here to determine how “colorless” a diamond can be. You want your diamond to face up with as little trace of yellow as you can, unless you are buying a fancy colored diamond.

Remember, the difference between a colorless and near colorless diamond can sometimes be hard to detect. It also can depend on if you are setting it in white gold, yellow gold or rose gold. Therefore, knowing the color grading of your diamond is very important.

The color of a diamond is universally measured by either D-Z scale of the GIA or 0-10 scale of the AGS (Figure 2)

View three different color grades beside each other to see if there is a significant difference.

Ask to place the diamond against a white background.

Remember that the above scales are not used to measure the color of fancy colored diamonds.

Pear-shaped blue diamond ring
Diamond color is graded using two universally accepted grading systems:
1. GIA Grading System (Gemological Institute of America)
2. AGS Grading System (American Gem Society)
Pear-shaped blue diamond ring
Diamond clarity is graded using two universally accepted grading systems:
1. GIA Grading System (Gemological Institute of America)
2. AGS Grading System (American Gem Society)


Even diamonds can have imperfections! These imperfections are called “Inclusions” if they are inside the diamond, and “blemishes” if they are on the surface of the diamonds. Generally, your higher clarities require a minimum of 10X magnification and your lower ones can be seen with your eyes.

Clarity of a diamond is also a very important factor affecting its value, beauty and integrity. Again there are two different scales from the GIA and the AGS are used determine diamond clarity (figure 3).

Step cut diamonds such as Emerald cut and Asscher cut diamonds should have atleast a VS2 clarity in them as oppose to a Round, Oval, Princess, Pear, Cushion or Radiant cut diamond, which can hide imperfections a little better.

This is a C that you should trust your eyes and pay for what you can see and not with what you don’t see.


The fourth C refers to the weight of the diamond or the Carat Weight of the diamond. Diamonds and all other gemstones are weighed using carats. One carat is equal to 0.2 grams.

Remember carat is not the same as karat that determines the purity of gold.

The carat weight of a diamond alone cannot be used as a fair reflection of its beauty in terms of sparkle and brilliance. Think about this. What good is it to be wearing an insanely huge diamond ring when the stone itself has no pop! No matter the carat size of the diamond, you always want to refer back to the first C, Cut.

Rayna Lonzano

Our Master Gemologist, Dino Lonzano, is a Gemological Institute of America graduate in Diamond Essentials, Colored Stone Essentials, Jewelry Essentials, Gem Identification, and Colored Stone Grading. Dino was born into the business, and grew up helping his dad and Uncles at their shops in Silver Spring, Maryland with jewelry creations and luxury watch repair. Now with more than four decades of experience, Dino has literally seen, cut, and valued millions of dollars’ worth of diamonds and colored stones. He is very hands on and reviews every offer to ensure his customers are getting the best care possible.