Laboratory-grown diamonds have moved from a specialist alternative into a major part of the engagement-ring and fine-jewellery market. Their growth is most visible in bridal jewellery, where buyers can often compare larger centre stones, more shapes and custom designs within the same overall budget.
That growth does not mean laboratory-grown diamonds lead every jewellery category or that every retailer has the same experience. Survey data, retail transactions and insurance-based datasets measure different parts of the market. Buyers should understand what each statistic represents before treating it as evidence for the entire jewellery industry.
Quick answer :
Laboratory-grown diamonds became the majority centre-stone choice in The Knot Worldwide’s survey of 2025 engagement-ring purchases, published in February 2026. Their appeal is strongly connected to purchase price, available size and design flexibility. Buyers should still compare cut quality, reports, treatments, retailer policies, resale expectations and the evidence behind environmental claims.
What Does the 2026 Market Data Actually Show?
The strongest evidence of laboratory-grown diamond adoption comes from engagement-ring purchasing rather than from every category of diamond jewellery.
The Knot Worldwide’s 2026 Real Weddings Study, published on 18 February 2026 and based on 2025 purchasing, reported that:
- 61% of engagement rings featured laboratory-grown centre stones.
- 40% of couples said it was specifically important that their stone be laboratory-grown.
- The average laboratory-grown centre stone was 1.9 carats.
- The average reported spend for a laboratory-grown engagement ring was $4,600.
These figures show leadership within that survey’s engagement-ring sample. They do not prove that laboratory-grown diamonds account for most revenue, most units or most inventory across every type of jewellery retailer.
Retail transaction data also shows why market share and financial performance should be analysed separately. Tenoris reported that loose laboratory-grown diamond unit sales increased during 2025 while category revenue declined slightly and prices continued to fall. In the first half of 2026, jewellery set with laboratory-grown diamonds produced double-digit revenue growth, while June growth was driven mainly by increased unit sales rather than higher average spend per purchase.
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How to read market statistics: Check whether a percentage refers to centre stones, loose diamonds, finished jewellery, unit sales, revenue, insured purchases or survey responses. Those measurements should not be treated as interchangeable.
Why Are Buyers Choosing Laboratory-Grown Diamonds?
The purchasing decision usually involves a combination of budget, visible size, design flexibility and personal preference. It should not be reduced to one claim about ethics or sustainability.
More visible size within a defined budget
Laboratory-grown diamonds commonly allow buyers to consider a larger carat weight or allocate more of the budget to the setting, metal, accent stones or custom details. The Knot’s reported 1.9-carat average centre stone illustrates the role that size plays in this category.
Carat is a measure of weight, not face-up diameter. Two diamonds with the same weight can appear different in size because of their shape, proportions and cutting depth. Buyers should compare millimetre measurements as well as carat weight.
Wider design flexibility
A lower centre-stone purchase price can make room for:
- Larger centre diamonds
- Hidden halos and accent stones
- Three-stone or side-stone designs
- Bridal ring sets
- Platinum or higher gold weight
- Custom engraving
- Fancy shapes or coloured laboratory-grown diamonds
More online comparison
Online shoppers can compare report numbers, dimensions, shape, carat weight, colour, clarity, cut and setting details across many products. This makes clear product specifications and accurate filtering especially important.
Readers comparing current prices can use Rosec Jewels’ lab-grown diamond price guide for 2026.
Are Laboratory-Grown Diamonds Real Diamonds?
Yes. A laboratory-grown diamond is diamond material produced through a manufacturing process rather than through geological formation beneath the earth.
Laboratory-grown diamonds have essentially the same chemical composition, crystal structure, optical characteristics and physical properties as natural diamonds. They are different from diamond simulants such as cubic zirconia and moissanite, which are separate materials.
Their similar properties do not make origin impossible to identify. Natural, HPHT-grown and CVD-grown diamonds develop under different conditions, leaving growth-related characteristics that specialised laboratories and screening instruments can detect.
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For a deeper explanation, read Are Lab-Grown Diamonds Real?
CVD, HPHT and Post-Growth Treatments
Gem-quality laboratory-grown diamonds are produced mainly through two methods: high pressure, high temperature and chemical vapour deposition.
HPHT diamonds
The HPHT process uses high pressure and high temperature to create conditions in which carbon crystallises around a diamond seed. The method can produce colourless and coloured diamonds.
CVD diamonds
The CVD process breaks down carbon-rich gas in a controlled chamber. Carbon atoms accumulate on thin diamond seeds, gradually building diamond crystal layers.
Does one method automatically produce a better diamond?
No. CVD and HPHT describe how the diamond was grown, not whether the finished stone is beautiful. Cut quality, proportions, colour, clarity, transparency, strain, polish, symmetry and post-growth treatment can all affect the result.
Some CVD-grown diamonds receive post-growth HPHT treatment to improve or change colour. A recognised laboratory report may identify the growth method and whether evidence of post-growth treatment was detected, depending on the report service.
Learn more about the manufacturing processes in Rosec Jewels’ guide to how laboratory-grown diamonds are made.
GIA and IGI Lab-Grown Diamond Reports in 2026
One of the most important 2026 buying developments is that GIA and IGI no longer present laboratory-grown diamond quality in exactly the same way.
On 1 October 2025, GIA introduced a revised quality-assessment system for qualifying D-to-Z laboratory-grown diamonds. Instead of using the full natural-diamond nomenclature on these new assessments, qualifying diamonds receive an overall classification of Premium or Standard.
IGI has stated that it will continue using full 4Cs grading for both natural and laboratory-grown diamonds. An IGI laboratory-grown diamond report can include carat weight, colour, clarity, cut information where applicable, polish, symmetry, measurements, growth-method information and treatment comments.
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A seller-issued authenticity certificate and an independent gemological report are not necessarily the same thing. Buyers should identify the issuing organisation and read exactly what the document confirms.
How to Verify a Laboratory-Grown Diamond Report
Before relying on a grading document, match it to both the diamond and the product listing.
- Check the issuer: Confirm whether the document comes from GIA, IGI or another named organisation.
- Verify the report number: Use the laboratory’s official online report-check service.
- Confirm origin: The document should clearly identify the diamond as laboratory-grown.
- Compare the measurements: Match the shape, carat weight and millimetre dimensions to the listing.
- Review the quality fields: Understand whether the document uses a full 4Cs format or an overall quality assessment.
- Check growth and treatment comments: Look for CVD, HPHT and any detected post-growth treatment when the report provides that information.
- Ask about the inscription: Determine whether the report number appears on the diamond’s girdle.
- Check what was examined: Establish whether the report covers a loose centre diamond or a complete finished jewellery piece.
Important: A grading report describes the submitted diamond. It does not guarantee future resale value, the strength of the ring setting, the seller’s return policy or the quality of after-sales service.
Pricing, Retailer Margins and Inventory Risk
Lower laboratory-grown diamond prices can benefit buyers, but falling prices also create challenges for retailers holding inventory.
Tenoris reported that loose laboratory-grown diamond prices declined 13% during 2025. Unit sales increased, but revenue declined slightly. Retailers responded by increasing percentage margins and relying more heavily on memo inventory, which can be returned to suppliers when it does not sell.
This illustrates why a high margin percentage does not necessarily mean a retailer earns more money per stone. Retail economics should distinguish:
- Margin percentage
- Gross profit per item
- Unit sales
- Total category revenue
- Average selling price
- Inventory ageing
- Price paid to replace sold inventory
Why can laboratory-grown diamond prices change quickly?
Production capacity, manufacturing efficiency, competition, wholesale supply, quality improvements and retailer pricing strategies can all influence prices. The setting’s metal, craftsmanship and accent stones may not decline at the same rate as the centre diamond.
How should buyers compare prices?
Compare like with like:
- Same shape and carat weight
- Similar face-up dimensions
- Comparable colour and clarity information
- Similar cut, polish and symmetry
- Same metal purity and approximate metal weight
- Same accent-stone specifications
- Comparable report type
- Similar return, resizing and warranty terms
A low price is not automatically a bargain when the diamond has weak proportions, reduced transparency, poor light return or an unclear report.
Do Laboratory-Grown Diamonds Hold Their Value?
Laboratory-grown diamonds should generally be purchased for their appearance, size and suitability for the intended jewellery—not with an assumption of investment appreciation.
Retail prices have changed as production and competition have expanded. A future second-hand offer may therefore be substantially lower than the original retail price. The resale market can also depend on the buyer, report, diamond specifications, jewellery condition, brand, metal value and whether the retailer offers a trade-in or upgrade programme.
Natural diamonds also do not guarantee a profitable resale. Retail purchase price, insurance replacement value, appraisal value, dealer buyback and private resale value are different concepts.
Questions to ask about future value
- Does the retailer offer a written upgrade or trade-in programme?
- Does that programme apply to laboratory-grown diamonds?
- Are there minimum-spend or condition requirements?
- Does customisation affect eligibility?
- Is the report and original paperwork required?
- What part of the original purchase price is considered?
Do not rely on verbal assurances about resale. Ask for the applicable policy in writing.
Are Laboratory-Grown Diamonds Automatically Sustainable?
Laboratory growth avoids conventional diamond extraction, but that does not establish the complete environmental or social impact of every stone.
The footprint can vary according to:
- CVD or HPHT production method
- Electricity source
- Facility efficiency
- Growth duration and yield
- Post-growth treatment
- Cutting and polishing location
- Metal sourcing
- Jewellery manufacturing
- Packaging and transportation
Broad descriptions such as “eco-friendly,” “green,” “carbon-conscious,” “sustainable” or “ethical” should be supported by clear, specific evidence. The FTC’s Green Guides advise marketers not to make broad, unqualified environmental-benefit claims because those claims can imply benefits that are difficult to substantiate.
Better questions for buyers
- Where was the diamond grown?
- What energy source was used?
- Is the claim independently verified?
- Does the claim apply to the diamond, the metal or the complete ring?
- Are cutting and manufacturing locations disclosed?
- Does the evidence cover the actual supplier or only the industry in general?
A laboratory-grown diamond may fit a buyer’s priorities, but origin alone should not be treated as complete proof of environmental or ethical performance.
What Should Retailers Disclose?
The FTC advises sellers to identify laboratory-created diamonds clearly so shoppers understand that they are not mined diamonds. The origin qualifier should appear immediately with the word “diamond” and be equally conspicuous.
A complete product listing should state:
- Laboratory-grown origin: The stone should not be described only as a “diamond” in a way that implies mined origin.
- Centre-stone specifications: Shape, carat weight, measurements and reported quality information.
- Growth method: CVD or HPHT when known and relevant.
- Post-growth treatment: Any known treatment affecting colour or appearance.
- Accent-stone origin: Whether accent diamonds are natural or laboratory-grown.
- Report issuer: The name of the laboratory or certificate provider.
- Metal information: Metal type, purity and colour.
- Product scope: Whether the stated carat weight refers to the centre stone or total diamond weight.
- Order terms: Return, exchange, resizing, cancellation and custom-order restrictions.
Total weight versus centre-stone weight
“Two carats” may refer to one two-carat centre diamond or to the combined weight of the centre and accent stones. The product page should make that distinction clear.
Custom orders
Customisation, engraving, resizing or made-to-order specifications can affect cancellation and return eligibility. Review the live policy before placing the order rather than assuming every item follows the same terms.
Rosec’s current terms can be reviewed on its return policy and shipping policy pages.
Laboratory-Grown Diamond Buyer Checklist
Use this checklist before purchasing a loose diamond, engagement ring or other laboratory-grown diamond jewellery.
- Define the budget: Include the setting, taxes, resizing and optional customisation—not only the centre diamond.
- Confirm the origin: Ensure “laboratory-grown” is displayed clearly in the title and specifications.
- Check the report: Identify the issuer, report type and report number.
- Verify the report online: Use the issuing laboratory’s official verification service.
- Compare measurements: Review face-up dimensions as well as carat weight.
- Prioritise cut: Sparkle depends heavily on proportions, symmetry, polish and light performance.
- Review transparency: A high colour and clarity grade does not automatically rule out haziness, strain or reduced transparency.
- Check treatments: Review growth-method and post-growth-treatment comments.
- Confirm accent stones: Determine whether side stones are natural diamonds, laboratory-grown diamonds or another material.
- Inspect the setting: Check prongs, stone security, band thickness, basket height and wedding-band compatibility.
- Read the policies: Confirm return, exchange, resizing, warranty and custom-order restrictions.
- Ask about upgrades: Obtain any trade-in or upgrade promise in writing.
Design a Ring That Feels Like Your Story
Explore IGI-certified lab-grown diamonds, handcrafted settings, ethical gemstones, and customizable engagement ring designs made for modern love.
Frequently Asked Questions
What percentage of engagement rings use laboratory-grown diamonds in 2026?
The Knot Worldwide’s study published in February 2026 reported that 61% of surveyed engagement-ring purchases made during 2025 featured laboratory-grown centre stones. This figure applies to that study’s engagement-ring sample and should not be interpreted as 61% of every diamond or jewellery sale.
Are laboratory-grown diamonds real diamonds?
Yes. They are diamond material produced through CVD or HPHT growth rather than geological formation. They have essentially the same chemical composition, crystal structure, optical characteristics and physical properties as natural diamonds. Specialised testing can still identify their laboratory origin.
Why do laboratory-grown diamonds cost less?
Their supply can expand through manufacturing, while natural-diamond supply depends on geological deposits and mining. Improving production efficiency, greater competition and changing wholesale prices also affect laboratory-grown prices. The final jewellery price still includes metal, accent stones, craftsmanship and service.
Does GIA use the 4Cs for laboratory-grown diamonds in 2026?
GIA changed its approach for qualifying D-to-Z laboratory-grown diamonds on 1 October 2025. Its current assessment uses Premium or Standard classifications based on defined colour, clarity and cut-related criteria rather than presenting the full natural-diamond nomenclature in the previous way.
Does IGI still provide full 4Cs grades for laboratory-grown diamonds?
Yes. IGI has stated that it continues to use the full 4Cs framework for natural and laboratory-grown diamonds. Its reports can include carat weight, colour, clarity, cut information, measurements, polish, symmetry and relevant comments.
Is a GIA Premium diamond better than an IGI-graded diamond?
The two documents use different presentation systems, so the labels should not be compared directly. Review the underlying information, diamond proportions, transparency, appearance and report scope rather than assuming one headline term automatically makes a stone superior.
Is CVD better than HPHT?
Not automatically. Both processes can produce attractive diamonds. The finished stone’s cut, colour, clarity, transparency, proportions, polish, symmetry and treatment history are more useful buying considerations than the growth method alone.
Do laboratory-grown diamonds hold their value?
Future resale is uncertain and can be substantially below the original retail price. Production capacity and declining retail prices can affect second-hand demand. Natural diamonds also do not guarantee profitable resale. Buyers should purchase primarily for use, design and appearance.
Are laboratory-grown diamonds always more sustainable?
No universal conclusion applies to every producer. Laboratory growth avoids conventional mining, but its footprint depends on electricity, facility efficiency, growth method, treatments, cutting, jewellery manufacturing and transportation. Look for specific evidence supporting any environmental claim.
Can a jeweller identify a laboratory-grown diamond by looking at it?
Reliable identification normally requires specialised equipment or laboratory testing. Natural and laboratory-grown diamonds can appear similar to the unaided eye, and older basic diamond testers may only confirm that the material behaves like diamond rather than determine its origin.
Does a grading report guarantee resale value?
No. A report records gemological characteristics and origin information. It is not automatically a monetary appraisal, buyback guarantee, warranty or promise of future value.
What is the most important quality factor?
Cut quality is often the most important factor in visible brightness and sparkle, especially for round brilliant diamonds. Colour and clarity matter, but a poorly proportioned high-grade diamond may appear less lively than a well-cut stone with more moderate grades.
Authoritative Sources
- GIA: Updated laboratory-grown diamond services
- GIA: Natural and laboratory-grown diamond identification
- GIA: HPHT and CVD diamond growth processes
- IGI: Continued 4Cs grading for all diamonds
- IGI: Laboratory-grown diamond reports
- FTC: Diamond and gemstone advertising disclosures
- FTC: Environmental Claims and Green Guides
Disclaimer: This article is provided for general education and market context. It is not a professional gemstone identification, financial appraisal, resale guarantee, environmental certification, legal opinion or investment recommendation. Market figures depend on the source, sample and methodology and may change over time. Review the live product specifications, report, policies and independent evidence relevant to the individual purchase.