Every Moissanite Shine stone comes with a GRA certificate — a document that certifies the stone's color grade, clarity grade, cut grade, and carat weight. But what does that certificate actually mean? What happens inside the GRA lab before that certificate is issued? And how do you verify that your certificate is genuine?
This guide takes you inside the moissanite grading process — from the moment a stone arrives at the lab to the moment the certificate is issued — so you understand exactly what you're buying and why the certification matters.
What Is the GRA?
The GRA (Gemological Research Association) is a gemological laboratory that specializes in the grading and certification of moissanite and other lab-created gemstones. It was established to provide independent, standardized quality assessment for the moissanite market — applying the same rigorous grading methodology used by the GIA (Gemological Institute of America) for diamonds to the moissanite category.
GRA certification is the industry standard for moissanite quality verification. A GRA certificate is an independent, third-party assessment of your stone's quality — not a manufacturer's claim or a retailer's representation, but a verified measurement performed by trained gemologists using calibrated equipment.
The Four Quality Factors — What the GRA Measures
1. Color Grade
Color grading is performed by trained gemologists who compare the stone to a set of master comparison stones under controlled lighting conditions. The stone is viewed face-down against a white background — the standard position for color grading — and compared to the master stones to determine its color grade on the D-Z scale.
The controlled lighting conditions are critical: color grading is performed under specific, standardized lighting that eliminates the variables of natural light, fluorescent light, and incandescent light. The grade reflects the stone's color in these controlled conditions, which is why the same stone may appear slightly different in different real-world lighting environments.
For moissanite, the GRA grades stones in three categories: DEF (colorless), GH (near-colorless), and IJ (faint color). Each grade represents a specific range on the D-Z scale, verified by comparison to master stones.
2. Clarity Grade
Clarity grading is performed under 10x magnification using a loupe or microscope. The gemologist examines the stone for inclusions (internal characteristics) and blemishes (surface characteristics), assessing their size, nature, number, position, and relief (how visible they are against the stone's background).
The clarity grade reflects the stone's appearance under 10x magnification — not to the naked eye. A VVS1 stone has inclusions that are extremely difficult to see even under 10x magnification. A VS1 stone has inclusions that are difficult to see under 10x magnification. Both grades are eye-clean — the inclusions are not visible to the naked eye in normal viewing conditions.
The GRA clarity scale for moissanite mirrors the GIA diamond clarity scale: FL (Flawless), IF (Internally Flawless), VVS1, VVS2, VS1, VS2, SI1, SI2, I1, I2, I3. In practice, moissanite is produced at VVS1 or better in most quality-controlled manufacturing processes.
3. Cut Grade
Cut grading is the most complex of the four quality factors because it encompasses multiple measurements: table percentage, depth percentage, crown angle, pavilion angle, girdle thickness, culet size, polish, and symmetry. Each of these measurements is taken using precision instruments, and the results are combined to produce an overall cut grade.
The GRA cut grades for round brilliant moissanite are: Excellent, Very Good, Good, Fair, and Poor. For center stones in fine jewelry, Excellent is the only appropriate grade — Very Good and below represent compromises in optical performance that are visible in real-world wear.
For non-round shapes (oval, cushion, pear, emerald, etc.), cut grading is more complex because there is no single ideal set of proportions for fancy shapes. The GRA assesses fancy shape cut quality based on outline, symmetry, and overall optical performance rather than a fixed set of proportions.
4. Carat Weight
Carat weight is the most straightforward of the four quality factors: the stone is weighed on a precision scale calibrated to 0.001 carat accuracy. One carat equals 0.2 grams. The weight is recorded on the certificate to the nearest 0.01 carat.
It's important to understand that carat weight is a measure of mass, not size. Two stones of the same carat weight may have different physical dimensions depending on their cut proportions. A well-cut stone will have dimensions that correspond predictably to its carat weight; a poorly cut stone may be heavier than its dimensions suggest (because excess weight is hidden in the depth) or lighter (because the stone is cut too shallow).
The Grading Process — Step by Step
Step 1: Stone receipt and logging. The stone arrives at the GRA lab and is logged into the system with a unique identifier. This identifier links the stone to its certificate throughout the grading process.
Step 2: Cleaning. The stone is cleaned to remove any surface contamination that could affect color or clarity grading. Even microscopic oils or residues can affect the grading result.
Step 3: Measurement. The stone's physical dimensions are measured using precision instruments: diameter (for round stones), length and width (for fancy shapes), and depth. These measurements are used to calculate the cut proportions and to verify the carat weight estimate.
Step 4: Weighing. The stone is weighed on a precision scale. The weight is recorded to 0.001 carat accuracy.
Step 5: Color grading. The stone is color-graded by at least two independent gemologists under controlled lighting conditions. If the two grades differ, a third gemologist grades the stone and the majority grade is recorded.
Step 6: Clarity grading. The stone is clarity-graded under 10x magnification by at least two independent gemologists. Any inclusions or blemishes are mapped on the certificate diagram.
Step 7: Cut grading. The stone's cut proportions are measured and the overall cut grade is calculated. Polish and symmetry are assessed separately.
Step 8: Certificate generation. The grading results are compiled into a certificate with a unique certificate number. The certificate includes the stone's measurements, weight, color grade, clarity grade, cut grade, and a diagram showing the location of any inclusions.
Step 9: Laser inscription (optional). Many GRA-certified stones are laser-inscribed with the certificate number on the girdle (the thin edge of the stone). This inscription is visible under 10x magnification and allows the stone to be matched to its certificate at any time.
How to Verify Your GRA Certificate
Every GRA certificate has a unique certificate number that can be verified on the GRA's online database. To verify your certificate:
Step 1: Locate the certificate number on your GRA certificate (typically in the upper right corner).
Step 2: Visit the GRA's official website and navigate to the certificate verification page.
Step 3: Enter the certificate number and verify that the details on the website match the details on your physical certificate.
Step 4: If your stone has a laser inscription, verify that the inscription number matches the certificate number under 10x magnification.
A certificate that cannot be verified on the GRA's database is not a genuine GRA certificate. If you cannot verify your certificate, contact the seller immediately.
Why Certification Matters
A GRA certificate is your protection as a buyer. It's an independent, third-party verification of your stone's quality that cannot be altered or falsified without detection. It's the document that allows you to:
Verify what you paid for: The certificate confirms that the stone you received matches the quality you were sold.
Insure your stone: Insurance companies require documentation of a stone's quality and value. A GRA certificate provides that documentation.
Resell or upgrade: When you use our Lifetime Upgrade Program, the GRA certificate is the document that establishes your stone's value for the upgrade calculation.
Have your stone serviced: When you take your ring to a jeweler for cleaning, resizing, or repair, the GRA certificate allows the jeweler to verify the stone's identity before and after the service.
Every Moissanite Shine stone comes with a GRA certificate. It's not optional — it's the foundation of the trust relationship between us and our customers.
For a complete explanation of what your GRA certificate means, see: GRA Certificate Explained: What It Is, What It Means & How to Verify Yours.
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Related guides:
GRA Certificate Explained: What It Is, What It Means & How to Verify Yours
Moissanite Color Grades Explained
Moissanite Clarity Grades Explained
Moissanite DEF vs GH vs Near-Colorless: The Real Difference
How to Spot Fake Moissanite: 7 Tests Every Buyer Should Know