Moissanite Grading System Explained: How Moissanite Is Evaluated and Graded

When you purchase a moissanite stone, it comes with a grade — a set of evaluations describing the stone's color, clarity, cut quality, and other measurable properties. These grades are recorded on the GRA certificate and determine, in a systematic and reproducible way, what kind of stone you are purchasing.

The Moissanite Grading Framework

Moissanite grading uses a framework adapted from the GIA diamond grading system, which established the 4Cs — Color, Clarity, Cut, and Carat — as the universal language of gemstone quality. Moissanite uses the same scales with specific adjustments where silicon carbide's properties differ from diamond's. Read more: Moissanite 4Cs Equivalent Explained.

Color Grading

Moissanite color grading evaluates the presence or absence of tint in the stone. The scale is adapted from the GIA diamond D–Z scale, condensed into three practical grades:

• DEF — Colorless: Equivalent to D, E, F on the GIA diamond scale. No discernible color to the naked eye under any standard lighting condition. All Moissanite Shine stones are DEF colorless.
• GHI — Near-Colorless: Very slight warmth detectable only by a trained grader under controlled conditions — invisible in normal jewelry settings. Appropriate for warm metal settings (yellow gold, rose gold).
• JKL and below — Faint Color: Visible warmth or tint without magnification. Not used in Moissanite Shine products.

Note: silicon carbide's double refraction can produce a slight grayish or greenish appearance under certain lighting (particularly fluorescent) even in high-color-grade stones. This is a material property, not a grading defect. DEF color and Excellent cut minimize this tendency. Read more: Moissanite Color Grades: DEF vs. GHI.

Clarity Grading

Clarity evaluates internal inclusions and surface blemishes, on a scale adapted from GIA diamond grading:

• FL / IF: No inclusions under 10x magnification. Extremely rare in moissanite; practically indistinguishable from VVS1 in appearance.
• VVS1 / VVS2: Inclusions extremely difficult to detect under 10x magnification — completely invisible to the naked eye. All Moissanite Shine stones are VVS1.
• VS1 / VS2: Inclusions difficult to detect under magnification, invisible to the naked eye. An excellent practical clarity grade.
• SI1 / SI2: Inclusions visible under magnification; may be visible to the naked eye in larger stones. Not used in Moissanite Shine products.

The practical threshold: any stone VS1 or above is eye-clean. The upgrade from VS1 to VVS1 is a quality guarantee, not a visible appearance difference. Read more: Moissanite Clarity: VVS1 Explained.

Cut Grading

Cut grading evaluates the precision of the stone's faceting — the angles, proportions, symmetry, and polish that determine how the stone handles light. Cut is the most important quality factor for optical performance. The scale: Excellent, Very Good, Good, Fair, Poor. All Moissanite Shine stones carry Excellent cut, polish, and symmetry — the highest possible grades. Read more: Moissanite Cut Quality Guide.

Carat Weight and Diamond Equivalent Weight (DEW)

Moissanite has a specific gravity of 3.21 vs. diamond's 3.52 — meaning a moissanite stone of the same physical dimensions as a diamond weighs approximately 10% less. When moissanite is described as "1 carat," sellers typically mean 1 carat DEW — the same physical dimensions as a 1-carat diamond, not 1 carat of actual moissanite weight. Read more: Moissanite Size Guide.

What the Grading Combination Means in Practice

All Moissanite Shine stones are DEF / VVS1 / Excellent cut, polish, and symmetry — the highest practical quality standard for moissanite in fine jewelry. This combination delivers maximum optical performance, no visible color, and no visible inclusions under any normal viewing condition.

Explore our moissanite collection — GRA-certified, backed by our Lifetime Gemstone Warranty. Read your certificate: How to Read Your Moissanite Certificate.

Related guides:
Moissanite 4Cs Equivalent Explained
How to Read Your Moissanite Certificate
Moissanite Color Grades: DEF vs. GHI
Moissanite Clarity: VVS1 Explained
Moissanite Cut Quality Guide