CLARITY

Transparency—whether the stone is free of inclusions and blemishes.

A diamond with no internal or external flaws that hinder the passage of light earns the highest grade, FL (Flawless). From there, clarity is divided into 11 levels according to the type, size, and visibility of inclusions.

What’s evaluated?

Inclusions and surface blemishes: their type, size, position, and number. A grader examines the stone under 10× magnification and assigns a clarity grade based on what is found inside and on the surface.

Grade guide

The scale runs from “nothing visible” to “easily seen with the naked eye,” in 11 steps—Flawless → Internally Flawless → VVS → VS → SI → I. The farther you go down the alphabet, the easier it is to see tiny “dots” or “lines” without magnification.

Analogy

Think of a snow globe: the fewer snowflakes (inclusions), the clearer the scene; the more flakes, the cloudier the view.

Practical tip

Above VVS it becomes hard to notice differences with the naked eye. Within the same budget, you may experience more visible sparkle by investing in better cut or carat weight rather than pushing clarity higher.

COLOR

Diamonds are graded for subtle differences in body color, ranging from colorless to light yellow. The scale runs from D (completely colorless) down to Z (light hue). A D-color stone is pure, icy white and considered the highest quality in color grading.

What’s evaluated?

The closer a diamond comes to absolute colorlessness, the higher its grade. Grade D sits at the pinnacle; as faint traces of yellow or brown increase, the grade drops to E, F, and so on down to Z.

How it appears

Color is more noticeable in thicker stones. In diamonds over 1 ct, the difference between E and G is often visible to the naked eye, whereas in a 0.3 ct stone it may be hard to detect.

Everyday analogy

Picture adding one drop of lemon juice to a glass of water. If the glass is full, the color looks pale; if there’s little water, the same drop appears much darker.

Exception

Fancy colors—pink, blue, and so on—are graded separately. For these, the rule reverses: the richer the color, the rarer and more valuable.

CARAT

What does it measure?

Carat (ct) is a unit of weight, not size; 1 carat equals 0.2 g. Because it measures weight, two diamonds that each weigh 1 ct can differ in face-up diameter depending on how they are cut.

Everyday analogy

A kilogram of cotton and a kilogram of iron weigh the same, yet their volumes are very different. Likewise, a deep-cut diamond shows a smaller table, while a shallow-cut stone looks broader.

Carat alone does not define value

Price generally rises with carat weight, but a diamond’s true value comes from the balance of all the 4 Cs—not carat alone.