Diamond Certificate Guide: Diamond & Jewellery Certifications Explained

Diamond Certificate Explained

A diamond certificate helps you verify authenticity, compare quality, insure your diamond, and protect its long-term value. It acts as the true passport of your diamond – confirming every critical detail, from the 4Cs to craftsmanship and real market worth. With the right certification, you’re not just buying a diamond; you’re securing clarity, transparency, and complete peace of mind.

Authentic certification logos from GIA, IGI, SGL, along with BIS hallmarking, ensure quality assurance you can trust.

Authentic diamond certificate logos from GIA, IGI, SGL, and BIS hallmark for quality assurance.
BIS and GIA certified diamond authenticity and grading logos
Diamond grading certificate showing cut, color, clarity, and carat details for verified diamond retailers

What Is a Diamond Certificate?

A diamond certificate, also called a diamond grading report, is an independent evaluation issued by a recognized gemological laboratory. It confirms the diamond’s identity and provides detailed grading on its carat weight, color, clarity, cut, and exact measurements.

At Ocean Star Diamonds & Jewellery, every loose diamond is supplied with trusted certification from GIA, IGI, SGL, or BIS, all widely recognized in Indian and international markets. This guide explains what your diamond certificate includes, how to read it correctly, and how to verify it online.

Why a Diamond Certificate Matters

A certified diamond is more than a stone; it’s an investment in trust and transparency. Here’s why diamond certification is essential:

  • Asset Protection: A diamond certificate is required for insurance appraisal and claims.

  • Resale Value: Certified diamonds retain market value better over time.

  • Buyer Confidence: Certification protects buyers from overgrading and misrepresentation.

When purchasing a loose diamond, a diamond certificate ensures you are paying the right price for the quality you receive.

What a Diamond Certificate Includes

The core of any diamond certificate is the assessment of the internationally accepted 4Cs. Understanding these parameters is essential for evaluating value.

Laser Inscription

All certified stones have the certificate number laser-engraved on the girdle for authenticity.

Carat Weight

This refers to the physical weight of the diamond, not its size dimensions. One carat equals 0.200 grams.

  • Note: Two diamonds of equal carat weight can have vastly different prices depending on the other three Cs.

Color Grade

Diamonds are graded on a scale of lack of color.

  • D – F: Colorless (Rarest and most valuable).
  • G – J: Near Colorless (Excellent value, minimal color visible to the naked eye).
  • K – Z: Faint to Light Yellow.
  • Fancy Colors: Graded differently, focusing on hue and saturation (e.g., Fancy Vivid Yellow).

Clarity Grade

This measures internal inclusions and external blemishes under 10x magnification.

  • FL / IF: Flawless / Internally Flawless.
  • VVS1 / VVS2: Very, Very Slightly Included.
  • VS1 / VS2: Very Slightly Included (Standard for high-end retail).
  • SI1 / SI2: Slightly Included.

Cut Grade

(Standard for Round Brilliants) This assesses how well the diamond interacts with light.

  • Excellent / Ideal: Maximum fire and brilliance.
  • Very Good: Reflects most light.
  • Good / Fair: Allows light to escape through the side or bottom.

Diamond Certificate Technical Specifications Explained

Beyond the 4Cs, the “Additional Grading Information” section impacts the stone’s price and performance.

Polish & Symmetry

  • Polish: The smoothness of the diamond’s facets. Poor polish can dull the sparkle.
  • Symmetry: The alignment of the facets. Misalignment reduces light reflection.
  • Our Standard: We prioritize “Triple Excellent” (Cut, Polish, Symmetry) or “Very Good” makes for optimal brilliance.

Fluorescence

This refers to the diamond’s reaction to UV light (usually emitting a blue glow).

  • None / Faint: Preferred for investment-grade colorless stones (D-F).
  • Medium / Strong: Can make lower color stones (I-J) appear whiter but may cause haziness in D-F stones.

Dimensions

Listed in millimeters (Length x Width x Depth). This confirms the actual visual size of the stone, ensuring it is not “deep” (hiding weight in the bottom) or “shallow.”

Jewelry Certification (SGL/IGI)

For finished jewellery (rings, necklaces, bracelets), the certification format differs slightly from loose stones. These reports authenticate the entire piece.

Key Data Points:

  • Gross Weight: Total weight of the metal and stones combined.
  • Net Metal Weight: Estimated weight of the Gold or Platinum content.
  • Stone Count: Total number of diamonds set in the piece.
  • Estimated Grades: Since stones are graded after setting, color and clarity are provided as a range (e.g., F-G Color, VVS-VS Clarity).
  • Hallmark: Verification of the metal purity (e.g., 18K / 750).

How to Verify a Diamond Certificate Online

Every certificate can be instantly verified on the lab’s official website:

LaboratoryVerification Link
GIA CertificationGIA Report Check
IGI CertificationIGI Verify
SGL CertificationSGL Report Verification

Steps to Verify:

  1. Locate the Report Number on the PDF or card.

  2. Enter the number (and weight if requested) on the lab website.

  3. Ensure digital data matches your physical certificate exactly.

Diamond Certificate Comparison: GIA vs IGI vs SGL vs BIS

FeatureGIAIGISGLBIS
Global RecognitionVery HighHighMediumIndia-Focused
StandardizationStrictModerateModerateStrict for Hallmark
4Cs AccuracyExcellentVery GoodGoodGood for Jewelry
VerificationOnlineOnlineOnlineOnline / Offline

Disclaimer & Limitations

  • All certificates represent the opinion of the respective lab
  • Labs may grade differently (minor variations normal)
  • Certificate does not guarantee resale price
  • Color perception may vary slightly under different lighting
  • Ocean Star is not responsible for lab-to-lab grading changes
  • Once the Buyer verifies in writing, the stone is not returnable except mismatch/defect

Video Verification and Plotting

Certificates often include a “Plotting Diagram” – a map showing the location of inclusions (feathers, crystals, pinpoints).

How to use our 360° Videos: We provide high-definition 360-degree videos for our loose inventory. You can cross-reference the inclusions shown on the certificate plot with the actual video to verify that the stone matches the report. This ensures 100% confidence in the identity of the diamond.

FAQs

1. What is a diamond certificate and why is it important? ▾
A diamond certificate proves authenticity, quality, and value. It protects your investment, ensures resale value, and is required for insurance.
2. Which is better: GIA certified diamond or IGI certified diamond? ▾
GIA is the global gold standard for grading accuracy, while IGI is widely trusted in retail markets. Both are recognized in India.
3. How do I verify a diamond certificate online? ▾
Locate the report number on the certificate and enter it on the official lab website. Match the details exactly.
4. Are jewelry certificates different from diamond certificates? ▾
Yes. Jewelry certificates cover the entire piece, including metal weight, stone count, and hallmark verification.
5. Is a diamond certificate required for insurance? ▾
Yes. Insurers require a certified report for appraisal and claims.

Contact

  • Ocean Star Diamonds & Jewellery
  • 3, Savani Ind. Soc., Kohinoor Road, Mini Bazaar,
     Surat – 395006
  • Website: ocsdiamond.com
  • Sales: +91-9510640173
  • Accounts: +91-8200524191
  • Email: info@ocsdiamond.com