IGI Certification for CVD Lab-Grown Diamonds: A Complete Buyer’s Guide

When shopping for a lab-grown diamond, you may encounter two important terms: CVD and IGI-certified.

CVD describes how a laboratory-grown diamond was created. IGI certification—or, more precisely, an IGI Laboratory Grown Diamond Report—documents what the finished diamond is and how its quality characteristics were evaluated.

In simple terms, an IGI-certified CVD lab-grown diamond is a diamond created through Chemical Vapor Deposition and subsequently examined by the International Gemological Institute. Depending on the report, IGI may confirm its laboratory-grown origin, identify the CVD growth method, evaluate the 4Cs, record additional characteristics, and issue a unique report that can be verified online.

Understanding what that report includes—and what it does not include—can help customers make more informed jewelry decisions.

What Is IGI Certification?

IGI stands for the International Gemological Institute, an independent organization specializing in the analysis and grading of diamonds, gemstones, and finished jewelry.

IGI began grading laboratory-grown diamonds in 2005. It now issues reports for qualifying loose laboratory-grown diamonds and finished laboratory-grown diamond jewelry. According to IGI, its reports identify diamond origin and document relevant characteristics according to established gemological standards. Learn more about IGI Laboratory Grown Diamond Reports.

Although shoppers commonly use the phrases “IGI certificate” and “IGI-certified diamond,” the official document is generally called an IGI Laboratory Grown Diamond Report.

That distinction is important. An IGI report is an independent gemological assessment of a specific diamond or jewelry item at the time it was examined. It is not automatically:

• A monetary appraisal
• An estimate of retail or resale value
• A guarantee of future value
• A jewelry warranty
• An insurance policy
• Proof of sustainable or ethical production
• A guarantee that a customer will find the diamond visually attractive

Its primary purpose is to provide documented information about the submitted item’s identity and observable characteristics.

What Is a CVD Lab-Grown Diamond?

CVD stands for Chemical Vapor Deposition, one of the principal methods used to produce laboratory-grown diamonds. The other widely used method is HPHT, or High Pressure High Temperature.

During the CVD process:

1. A thin diamond seed is placed inside a controlled growth chamber.
2. Carbon-containing gases, commonly involving a hydrocarbon such as methane, are introduced.
3. Energy converts the gases into plasma.
4. Carbon atoms separate from the gas.
5. The carbon collects on the diamond seed and forms diamond crystal material layer by layer.

The resulting material can be cut and polished into round, oval, emerald, cushion, pear, marquise, and other familiar diamond shapes. GIA provides a more technical overview of the CVD diamond growth process.

A CVD laboratory-grown diamond is not the same as cubic zirconia, glass, or moissanite. Those materials are diamond simulants. Laboratory-grown diamonds possess essentially the same optical, physical, and chemical properties as mined diamonds, but their origin is different.

The Federal Trade Commission requires that this origin be disclosed clearly. Sellers should use qualifying terms such as “laboratory-grown” or “laboratory-created” immediately before “diamond” so customers understand that the stone was not mined. Review the FTC’s jewelry advertising guidance.

It is also important to understand that CVD is a growth method—not a quality grade. CVD laboratory-grown diamonds can differ significantly in color, clarity, cut, proportions, fluorescence, and appearance.

Why IGI Certification Matters for CVD Lab-Grown Diamonds

1. It helps confirm laboratory-grown origin

A polished laboratory-grown diamond can look extremely similar to a mined diamond during ordinary viewing. Determining its origin reliably may require professional gemological analysis and specialized equipment.

IGI screens submitted stones to determine whether they are mined diamonds, laboratory-grown diamonds, or simulants. When reported, the comments section may also identify whether the laboratory-grown diamond was produced through CVD or HPHT.

2. It provides an independent quality assessment

Without a grading report, customers may be relying entirely on a seller’s description of the diamond.

Depending on the item and report format, an IGI report may document:

• Carat weight
• Color grade
• Clarity grade
• Cut grade, when applicable
• Shape and cutting style
• Measurements
• Proportions
• Polish
• Symmetry
• Fluorescence
• Clarity characteristics
• Growth-method information
• Post-growth treatment information
• Laser-inscription details

This creates a standardized foundation for comparing different stones.

3. It can provide information about post-growth treatment

Some CVD laboratory-grown diamonds undergo additional processing after growth to improve or modify their color. For example, a CVD diamond may receive HPHT treatment after the initial growth process.

Post-growth treatment does not turn a laboratory-grown diamond into a simulant. However, it is relevant information that customers should understand.

Depending on the report and the laboratory’s findings, comments may include language such as:

• “As Grown – No indication of post-growth treatment”
• “Indications of post-growth treatment”
• “May include post-growth treatment”

Report formats and disclosure wording can change. Customers should therefore rely on the exact wording shown on the individual report rather than assuming every CVD laboratory-grown diamond is untreated. Read IGI’s information about post-growth treatment reporting.

4. It creates a verifiable record

Each IGI report receives a unique report number. Customers can use this number to access the corresponding digital record through IGI’s verification system.

For individual laboratory-grown diamonds graded by IGI, the laboratory states that it automatically applies an inscription identifying laboratory-grown origin. The report number or related identifying information may also appear on the diamond’s girdle.

A qualified jeweler or gemologist can examine that inscription under magnification.

5. It makes diamond comparisons more meaningful

Two diamonds advertised as three-carat CVD laboratory-grown diamonds could have significantly different:

• Color grades
• Clarity grades
• Face-up dimensions
• Depth percentages
• Facet patterns
• Polish and symmetry grades
• Fluorescence
• Overall visual performance

An IGI report helps customers compare documented characteristics instead of relying only on carat weight, photographs, or marketing language.

How IGI Grades CVD Lab-Grown Diamonds

IGI describes a controlled grading process intended to support consistency, security, and objectivity. Ownership information is concealed from graders, and multiple gemologists may independently evaluate important characteristics.

Step 1: Anonymous intake

When a diamond enters the laboratory, it receives a unique identification number. Information identifying the owner is hidden from the graders.

This process is intended to allow the stone to be evaluated based on its gemological characteristics rather than the identity of the person or company that submitted it.

Step 2: Origin screening

IGI uses professional equipment and testing procedures to determine whether the submitted stone is:

• A mined diamond
• A laboratory-grown diamond
• A diamond simulant

Origin identification is more complex than using a basic retail diamond tester. Advanced screening, imaging, spectroscopy, and professional gemological assessment may be required.

Step 3: Carat weight and measurements

The diamond is weighed using a calibrated precision scale. One carat equals 200 milligrams, and the final carat weight is generally reported to two decimal places.

Optical measuring equipment records the diamond’s dimensions and geometry. Depending on the shape and report, measurements may include:

• Length
• Width
• Depth
• Table percentage
• Total depth percentage
• Girdle thickness
• Culet information
• Facet angles

Carat weight should not be confused with visible size. Two diamonds with the same weight can appear different in size because of their shape, proportions, and depth.

Step 4: Color and fluorescence

Diamond color is evaluated in a standardized viewing environment using calibrated master stones. Multiple graders can submit independent opinions before a final grade is established.

Within the traditional D-to-Z color-grading system:

• D–F is generally described as colorless
• G–J is generally described as near colorless
• Lower grades display progressively more noticeable tint

Fluorescence is also examined under ultraviolet light. If present, its strength—and sometimes its color—may be recorded on the report.

Step 5: Clarity

Clarity is evaluated at 10× magnification.

Gemologists examine the size, number, type, visibility, and location of internal characteristics and surface blemishes. Clarity grades may range from Flawless or Internally Flawless through VVS, VS, SI, and Included categories.

A higher clarity grade does not automatically mean a diamond will be more attractive to every customer. Some lower-clarity diamonds can still appear clean to the unaided eye, depending on the nature and position of their characteristics.

Step 6: Cut, polish, and symmetry

Cut is different from shape.

Round, oval, pear, emerald, marquise, and cushion describe a diamond’s shape. Cut evaluates the quality of its proportions and craftsmanship and how those factors influence its interaction with light.

For round brilliant diamonds, cut assessment can consider:

• Brightness
• Fire
• Scintillation
• Facet pattern
• Proportions
• Polish
• Symmetry

Polish evaluates the finish of the diamond’s facet surfaces. Symmetry evaluates the alignment and balance of its facets. Fancy-shape cut grading may be available when applicable.

Step 7: Independent verification and grading controls

Multiple gemologists may independently evaluate color and clarity. Final grades are established after the required level of agreement is reached.

IGI also describes tracking and central-control procedures between different stages of the grading process. Learn more about IGI’s diamond grading process.

Step 8: Report issuance and applicable inscription

After the grading process is completed, IGI issues the applicable report and makes a digital version available through its online system.

When an individual laboratory-grown diamond has an inscription, the inscription can help connect the stone with its report. However, the complete report information should always be compared—not only the inscription.

Understanding the 4Cs on an IGI Report

Carat weight

Carat measures weight, not visible diameter.

A deeply cut diamond may carry more of its weight below the girdle and appear smaller from the top than a diamond with a similar weight and different proportions.

Color

Color describes the amount of visible body color observed under standardized conditions.

The metal used in the jewelry can affect face-up appearance. For example, a near-colorless stone may look different when set in white gold than when set in yellow gold.

Clarity

Clarity measures the relative absence of internal characteristics and surface blemishes under 10× magnification.

Location matters. A characteristic near the edge of a diamond may be less noticeable than one positioned directly beneath the table.

Cut

Cut evaluates how effectively the diamond’s proportions and facet arrangement handle light.

A well-cut diamond can display strong brightness, fire, and movement. A poorly proportioned diamond may appear darker or less lively even if it has high color and clarity grades.

How to Read an IGI Laboratory Grown Diamond Report

Report formats can vary, but customers should review the following fields:

IGI also offers a guide explaining how to read an IGI Laboratory Grown Diamond Report.

Loose-Diamond Reports vs. Finished-Jewelry Reports

Not every IGI report covers the same type of item.

A loose-diamond report evaluates an individual diamond before it is mounted. This generally provides the laboratory with greater access to the stone and its physical characteristics.

A finished-jewelry report may describe:

• The complete jewelry item
• Mounted gemstones
• Precious-metal content
• Purity stamps
• Center-stone characteristics, as the mounting permits

If a ring has an individual report for its center stone, customers should not automatically assume that every accent or side diamond was individually graded or certified.

Before purchasing, ask:

• Does the report cover the individual center stone?
• Does it cover the completed jewelry item?
• Are the smaller accent stones included in the report?
• Does each applicable diamond have its own report?
• Which characteristics were limited by the mounting?

How to Verify an IGI Report Before Purchasing

1. Request the report number

Ask the seller for the applicable report number or digital report before completing the purchase.

2. Verify it through IGI

Enter the report number using IGI’s official verification system.

3. Compare the specifications

Confirm that the online report matches the seller’s description, including:

• Shape
• Measurements
• Carat weight
• Color
• Clarity
• Cut, when applicable
• Polish
• Symmetry
• Fluorescence
• Report comments

4. Confirm the growth method

If you specifically want a CVD laboratory-grown diamond, look for CVD in the report’s comments. Do not assume every laboratory-grown diamond was created through CVD.

5. Review treatment information

Read the exact post-growth treatment language shown on the report.

6. Check the inscription when practical

A qualified jeweler or independent gemologist can examine an accessible girdle inscription under magnification.

7. Keep all documentation

Retain the report, invoice, receipt, product description, and any written representations made at the time of purchase.

What an IGI Report Does—and Does Not—Establish

An IGI report is therefore a valuable source of information, but it should not be treated as a guarantee of price, beauty, investment performance, or product availability.

Why Customers Should Look for Independently Graded Stones

An independent grading report can help reduce uncertainty during the buying process.

It may allow customers to:

• Confirm laboratory-grown origin
• Understand documented quality
• Compare similar stones more accurately
• Identify CVD growth when reported
• Review applicable treatment information
• Verify the report independently
• Connect the diamond with its documentation
• Ask better questions before purchasing

Certification should be considered together with the jewelry’s design, metal, setting, construction, warranty, return policy, and overall craftsmanship.

Customers can also read our guide to choosing a trustworthy diamond jeweler.

Frequently Asked Questions

Is IGI certification appropriate for CVD lab-grown diamonds?

IGI grades qualifying laboratory-grown diamonds, including diamonds produced through the CVD process. Customers should review the individual report and verify its number directly through IGI.

Are CVD laboratory-grown diamonds considered diamond material?

They possess essentially the same optical, physical, and chemical properties as mined diamonds. However, they must be clearly described as laboratory-grown because they were produced in a controlled environment rather than mined.

Does an IGI report always identify CVD or HPHT growth?

Growth-method information may appear in the comments section. Report formats and comments can vary, so customers should inspect the specific report.

Are all CVD diamonds untreated?

No. Some CVD laboratory-grown diamonds undergo post-growth processing. The report comments should be reviewed for the applicable disclosure.

Is every laboratory-grown diamond IGI-certified?

No. A laboratory-grown diamond must be submitted to IGI for evaluation. Certification should never be assumed without an applicable report.

Is an IGI report the same as an appraisal?

No. A grading report documents gemological characteristics. An appraisal provides an opinion of monetary value for a particular purpose, such as obtaining insurance coverage.

Does an IGI report guarantee resale value?

No. A grading report does not guarantee a present or future selling price.

Can two diamonds with the same grades look different?

Yes. Shape, proportions, facet pattern, fluorescence, and other visual characteristics can produce noticeable differences between diamonds with similar grades.

Does one IGI report cover every diamond in a jewelry piece?

Not necessarily. A report may cover one loose center stone or a completed jewelry item. Customers should confirm exactly what the report evaluates.

Important Legal Disclaimer

This article is provided by Aminov Jewelry Company, LLC solely for general educational and informational purposes. It is not, and shall not be interpreted as, gemological, appraisal, valuation, investment, financial, legal, environmental, ethical, purchasing, or other professional advice. It does not constitute an offer to sell, a solicitation, a contractual promise, or a representation or warranty concerning any present or future product.

Aminov Jewelry Company, LLC and its owners may not manufacture, stock, offer, or sell lab-grown diamonds with IGI certification as described in this article. Nothing on this page represents or warrants that all—or any—laboratory-grown diamonds offered by Aminov Jewelry Company, LLC are CVD-grown, IGI-graded or IGI-certified, untreated, laser-inscribed, accompanied by an individual grading report, or consistent with any example, process, grade, inscription, treatment status, or reporting practice discussed above.

Inventory, suppliers, grading laboratories, report types, growth methods, treatments, inscriptions, product specifications, documentation, and availability may vary by item and may change at any time without notice. A report issued for one center stone should not be interpreted as applying to every accent stone, component, or piece of jewelry unless the applicable documentation expressly states otherwise.

Only the express written representations contained in the specific product listing, order confirmation, sales invoice, receipt, written warranty, and actual third-party grading report delivered with a particular purchased item apply to that transaction. If general information on this page differs from product-specific documentation, the product-specific documentation shall control, subject to Aminov Jewelry Company, LLC’s applicable terms, policies, and governing law.

Customers are solely responsible for reviewing all product-specific documentation before purchase, independently verifying any grading-report number through the issuing laboratory, confirming what stone or jewelry item the report covers, and obtaining advice from an independent qualified gemologist, appraiser, attorney, financial adviser, insurer, or other appropriate professional when necessary.

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