Your cart
Close Alternative Icon

Lucy & Mui's Signature Primer on the 4Cs

Arrow Thin Left Icon
Lucy & Mui's Signature Primer on the 4Cs

Here at Lucy & Mui, we strive to play professional matchmaker between you and the diamonds you buy. We work hard, sifting through hundreds of diamonds within your budget, to find the perfect stone for your needs. Though we’re happy to provide you with this service, handpicking the diamond that matches your wishes, many customers still want a foundational understanding of diamond ratings.

Here is our primer on the basics of diamond quality: the 4Cs by GIA, the internationally recognized authority on gemological knowledge.


Cut is the most important of the 4Cs. Why? Because cut determines the sparkle—the brilliance and fire—a diamond emits for the naked eye. Diamonds are professionally graded under a microscope, but what matters most to us are the starbursts of light that glitter in the sunshine, candlelight, and lamplight of our lives. Cut makes all the difference. A diamond with a low cut grade will appear dull and lifeless. A diamond with cuts too deep will appear much smaller than a well-cut diamond at a smaller carat size. Whether you prefer a round brilliant cut of 58 facets or a radiant cut with 70 facets, cut determines the beauty of your diamond in the light.


Carat is perhaps the most oft-discussed of the 4Cs. It refers to the mass of the diamond. One carat is defined as 200 milligrams. But carats can be further divided into 100 units, which are referred to as points. Thus, a .9-carat diamond is the same as a 90 pt. diamond. Many customers assume prices rise in direct proportion to carats. The truth is that prices increase steeply at specific mass milestones: half a carat, one full carat, and 1.5 carats. For many, a 90 pt. diamond looks nearly identical to a 1 carat diamond... But the price difference can be considerable.


Diamond colors begin at D (completely colorless) and end at Z (light yellow, sometimes with a brown tint). When similarly cut diamonds are rated within the same spectrum (D-F or G-I, for instance), it is difficult to see the difference in color. This confirms our belief that cut is the most important of the 4Cs.


Diamond clarity is determined by the number of imperfections in the stone. Blemishes are imperfections on the surface, while inclusions are internal defects. Though an imperfection on the table (the largest facet, top and center) will stand out, many imperfect diamonds look flawless to the naked eye. Most flaws are microscopic. If a diamond looks perfect to you, its clarity score will likely matter little in the end. Because of this, we consider clarity to be the least important of the 4Cs.


Purchasing an engagement ring—or any piece of diamond jewelry—is often an emotional investment. Buying a diamond means investing in a piece of adornment that will likely last in your family for generations. Then there is the added responsibility of spending thousands of dollars on one piece. It’s no wonder buying engagement rings can be stressful! That is why we adhere to your preferred budget. We ask your budget so we can make suggestions within your comfort zone. Helping you choose a centerstone involves sifting through hundreds of GIA-certified diamonds. Every diamond is different. We work hard to find the stone for you.

Our advice? You do the work of determining your budget, then leave the rest to us. We are pleased to spend the time handpicking your options so you don’t have to.

Comments on this post (2)

Leave a comment