Lab-grown diamonds have transformed the engagement ring market, offering consumers a choice that was unimaginable just two decades ago. These stones are chemically, physically, and optically identical to natural diamonds—composed of pure carbon arranged in a crystal structure—yet they're created in laboratories over weeks rather than deep in the Earth over billions of years. For many couples, lab-grown diamonds offer an appealing combination of beauty, value, and ethical clarity.
Whether you're considering a lab-grown diamond for ethical reasons, budget considerations, or simply curiosity, understanding how these stones are made, how they compare to natural diamonds, and what to look for when buying will help you make an informed decision.
How Lab-Grown Diamonds Are Made
Modern laboratories use two primary methods to create diamonds, both replicating the natural conditions that form diamonds deep within the Earth but on an accelerated timeline.
High Pressure High Temperature (HPHT)
The HPHT method mimics the conditions found about 150 kilometres below Earth's surface, where natural diamonds form. A small diamond seed is placed in pure carbon and subjected to approximately 1,500°C and 1.5 million pounds per square inch of pressure. Under these extreme conditions, the carbon melts and begins to form a diamond around the seed crystal. The process takes several weeks to grow a single rough diamond.
Chemical Vapour Deposition (CVD)
The CVD method is a newer technology that works quite differently. A thin diamond seed is placed in a sealed chamber and heated to around 800°C. The chamber is filled with a carbon-rich gas mixture (typically methane and hydrogen), and microwave energy causes the gas to form a plasma. Carbon atoms from the gas gradually deposit onto the seed, building up the diamond layer by layer. This process can take several weeks to a few months, depending on the desired size.
Key Point
Both methods create real diamonds—not simulants like cubic zirconia or moissanite. Lab-grown diamonds have the same hardness (10 on the Mohs scale), brilliance, fire, and physical properties as natural diamonds.
Lab-Grown vs. Natural: The Comparison
What's Identical
- Chemical composition: Both are pure crystallised carbon
- Physical properties: Same hardness, density, and thermal conductivity
- Optical properties: Identical brilliance, fire, and sparkle
- Appearance: Indistinguishable to the naked eye and even under standard magnification
- Durability: Both last forever and can be passed down through generations
What's Different
- Origin: Natural diamonds formed 1-3 billion years ago; lab diamonds are created in weeks
- Price: Lab-grown diamonds typically cost 30-50% less than comparable natural diamonds
- Resale value: Natural diamonds retain more resale value, though both resell well below retail
- Environmental impact: Lab-grown diamonds have a smaller environmental footprint (though not zero)
- Rarity: Natural diamonds are finite; lab diamonds can be produced indefinitely
The Ethical Considerations
For many consumers, ethics are a primary reason for choosing lab-grown diamonds. However, the ethical landscape is more nuanced than simple "good" versus "bad" narratives suggest.
Arguments for Lab-Grown
- Conflict-free certainty: Lab-grown diamonds have no connection to conflict zones or problematic mining operations
- Environmental impact: No land displacement, habitat destruction, or large-scale mining operations
- Transparency: Complete traceability from creation to purchase
- Worker conditions: Created in regulated laboratory environments
Considerations for Natural
- Economic impact: Diamond mining supports economies and communities in Africa and elsewhere, employing millions of workers
- Improved practices: The Kimberley Process and other initiatives have significantly reduced conflict diamonds (though imperfectly)
- Lab diamond energy use: Growing diamonds requires significant energy; the environmental benefit depends on energy sources
- Responsibly sourced natural: Some mines operate with high environmental and ethical standards
Key Takeaway
Neither option is perfectly "ethical" or "unethical." If ethical sourcing is important to you, research specific suppliers—whether lab-grown or natural—rather than relying solely on the category.
Quality and Grading
Lab-grown diamonds are graded using the same 4Cs system as natural diamonds: Cut, Colour, Clarity, and Carat weight. Major gemological laboratories including the GIA and IGI now certify lab-grown diamonds using the same standards applied to natural stones.
When shopping for lab-grown diamonds, apply the same quality criteria you would to natural diamonds:
- Prioritise cut quality for maximum sparkle
- Consider G-H colour grades for excellent value
- Look for eye-clean clarity (VS2 or SI1 typically)
- Balance carat weight against quality factors
Certification Matters
Always purchase lab-grown diamonds with certification from a reputable laboratory (GIA, IGI, or AGS). The certificate should clearly identify the diamond as laboratory-grown and provide a complete grading report.
The Price Advantage
The most compelling practical argument for lab-grown diamonds is price. A lab-grown diamond typically costs 30-50% less than a comparable natural diamond. This means you can either:
- Get a significantly larger diamond for the same budget
- Get higher quality grades (better cut, colour, clarity) for the same size
- Spend less overall and allocate funds elsewhere (honeymoon, home, savings)
For example, a natural 1-carat, G colour, VS2 clarity, Excellent cut diamond might cost $8,000-$12,000 AUD. A lab-grown diamond with identical specifications might cost $3,500-$5,500 AUD. The savings are substantial.
A Word About Resale
Lab-grown diamonds currently have lower resale value than natural diamonds. However, it's worth noting that even natural diamonds rarely resell for anywhere near their original retail price. If you're purchasing an engagement ring as an investment, diamonds in general—whether natural or lab-grown—aren't the best vehicle. Most people purchase engagement rings for their symbolic and emotional value, not financial returns.
Buying Tips for Lab-Grown Diamonds
What to Look For
- Reputable seller: Purchase from established jewellers with good reviews and clear policies
- Independent certification: Always require GIA, IGI, or AGS certification
- Clear disclosure: The diamond should be clearly identified as lab-grown throughout the sale process
- Return policy: Look for reasonable return windows to evaluate the stone in person
- Quality over size: Apply the same principles as natural diamonds—cut quality matters most
Common Questions
Can jewellers tell the difference? Not without specialised equipment. Lab-grown diamonds require laboratory testing to distinguish from natural diamonds. However, all certified lab-grown diamonds are laser-inscribed on the girdle for identification.
Do lab-grown diamonds last? Yes, forever. They have identical hardness and durability to natural diamonds. They won't cloud, fade, or deteriorate over time.
Should I tell people it's lab-grown? This is entirely personal. Some couples openly embrace their choice; others prefer to keep it private. There's no obligation either way—it's your ring and your decision.
Making Your Decision
Ultimately, the choice between natural and lab-grown diamonds comes down to personal values, priorities, and preferences. Neither option is inherently better—they're simply different.
Choose lab-grown if you prioritise budget efficiency, prefer guaranteed ethical clarity, or simply prefer the sustainability narrative. Choose natural if rarity and geological origins matter to you, if you prefer traditional choices, or if potential resale value is important.
Most importantly, choose what feels right for your relationship. The most meaningful engagement ring is one chosen thoughtfully, regardless of whether its carbon was formed in the Earth or in a laboratory.