I still remember the first time a couple walked into our studio clutching two diamond grading reports like they were exam papers. They placed them on the counter and said, half-whispering, “We’re stuck. IGI vs GIA lab grown — which one do we trust?”
Honestly, it’s a question I hear more often than “How long will the ring take?” These days, with man-made diamonds becoming the new normal in Aussie engagements, people are doing a lot more homework. They’re comparing certifiers, reading forums at midnight, and trying to decode the alphabet soup of grading labs.
If you’ve ever found yourself spiralling down a similar rabbit hole, you’re not alone. The truth? Most people don’t need a gemmology degree to choose a great diamond — they just need clear, real-world guidance. And that’s exactly what we’re diving into today.
As a jeweller who’s handled thousands of lab-grown diamonds from both IGI and GIA, I’ll walk you through how these two giants differ, when it actually matters, and why sometimes the debate gets blown way out of proportion.
Let’s take it from the top.
Table of Contents
Why the IGI vs GIA Debate Matters More These Days
A decade ago, lab-grown diamonds were more of a curiosity than a common purchase. They existed, sure, but they weren’t mainstream. Fast-forward to today, and — well — things have changed. You might not know this, but Australia is one of the fastest-growing markets for lab-grown stones, especially among younger couples who want luxury without the eyebrow-raising price tag.
And as demand has grown, so has the need for trustworthy, consistent certification.
When lab-grown diamonds first hit the scene, the IGI (International Gemological Institute) jumped in early. They weren’t just grading these stones — they were setting the standards. Meanwhile, the GIA (Gemological Institute of America), the world’s most respected grading authority, took its time. For years, GIA issued simplified reports for lab-grown stones, which frustrated jewellers and customers alike.
But in 2020, GIA changed its tune and began issuing full grading reports for lab-grown diamonds, putting both labs on a more level playing field.
Suddenly the debate reignited — IGI vs GIA lab grown — who does it better?
IGI vs GIA: The Personality Differences (Yes, They Have Them)
It’s funny, but diamond labs actually have their own quirks and personalities, a bit like coffee roasters or boutique wineries.
IGI: The Early Adopter
The IGI embraced lab-grown diamonds long before the traditionalists were ready. Their graders were trained early, their systems adapted quickly, and their reports became the benchmark for the lab-grown industry.
In plain terms:
If you’ve seen a lab-grown diamond in Australia, there’s a good chance IGI graded it.
They’re known for:
- consistency
- clear formatting
- predictable grading
- fast turnaround times
Gemmologists often say, “IGI is practical,” and honestly that’s pretty spot on.
GIA: The Traditionalist Turned Player
GIA has always been the gold standard for natural diamonds. They invented the 4Cs, so people naturally trust the name.
But they were cautious about lab-grown diamonds. Maybe too cautious.
Now that they’ve fully committed to grading lab-grown stones, their reports are superb — detailed, transparent, beautifully formatted — but with one caveat: GIA can be stricter in certain grading areas, especially colour.
Not inconsistent. Just stricter.
If IGI is the friendly early adopter, GIA is the perfectionist professor.
Here’s the Big Question: Do They Grade the Same Way?
Short answer?
Mostly — but not always.
Here’s what I’ve noticed over hundreds of stones:
Colour
GIA tends to grade colour slightly lower than IGI for the same diamond.
Not because the diamond is different — because GIA is simply more conservative.
For example:
-
An IGI F-colour diamond might come back as G colour at GIA.
Not always, but often enough that jewellers notice.
Clarity
Clarity grading is fairly aligned between the two labs. If IGI calls something VS1, GIA usually lands at VS1 or VS2.
Cut
Both labs grade cut well, but GIA is famously tough about proportions and symmetry. IGI is still strict — just not GIA strict.
Laser Inscriptions
Both labs laser-engrave report numbers on the girdle, so you can verify authenticity easily.
Report Format
Here’s where personal preference comes in.
Some people prefer IGI’s cleaner layout. Others love GIA’s classic, elegant format that feels more “luxury.”
Either way, reports from both labs are widely accepted in the industry.
Does the Certification Affect the Diamond’s Appearance?
This is the part many people misunderstand.
No — the diamond doesn’t change depending on who grades it.
A GIA VS1 diamond and an IGI VS1 diamond will look identical to the naked eye if they actually share the same characteristics.
What changes is:
- how the lab interprets the 4Cs
- how strict the grading is
- how detailed the report is
But the diamond itself? It’s exactly the same stone.
Pricing: Do IGI and GIA Affect What You Pay?
This is where things get interesting.
IGI-Graded Lab-Grown Diamonds
They’re common, widely stocked, and slightly more affordable simply because there’s more supply.
GIA-Graded Lab-Grown Diamonds
They’re usually priced a little higher — not because the diamond is better, but because the name “GIA” still carries serious industry prestige.
Some clients genuinely want that “GIA” stamp. And that’s fine.
Others don’t care and prefer an IGI stone with better specs for the same budget.
Neither group is wrong.
Are GIA Lab-Grown Reports Better?
Not necessarily. It depends on your priorities.
Choose GIA if you want:
- the industry’s most recognised name
- slightly stricter grading
- traditional prestige
Choose IGI if you want:
- great consistency
- excellent value
- clear, modern reports
- widely available stones at good prices
This breakdown from igi vs gia lab grown is actually a very fair comparison if you want to dig deeper.
The Elephant in the Room: Are Lab-Grown Diamonds “Real”?
Yes — 100% real carbon diamonds.
People still ask me this in 2025, and I honestly get it. There’s this lingering myth that lab-grown diamonds are “fake,” but in gemmology, that’s just not true.
A fake diamond is cubic zirconia or moissanite.
A lab-grown diamond is the same material as a mined diamond — just grown differently.
They’re chemically, optically, and physically identical.
And if you’re researching certification, you’re already well past the “are they real?” stage anyway. You’re looking for quality, accuracy, and legitimacy.
That’s smart.
The Role of Man-Made Diamonds in Modern Jewellery
If you’d asked me five years ago whether man-made diamonds would become mainstream, I probably would’ve hesitated. Today? They’re everywhere, and the range is phenomenal.
Couples aren’t just choosing them for price — though the savings are nothing to sneeze at. They’re choosing them because:
- they’re ethically produced
- they allow for larger stones
- they’re perfect for design-heavy custom work
One couple recently told me, “We wanted something bold and original. Why spend $20k when we can spend $6k and get exactly what we want?” And honestly, that’s the sentiment of a whole new generation of buyers.
If you’re curious about how they fit into the broader jewellery market — or if you’re exploring budget-friendly ring options — this piece on man made diamonds is a surprisingly good read.
Here’s What I Tell Customers Who Can’t Decide
After all the technical comparisons, people sometimes look even more overwhelmed than when they started. So here’s the advice I give, every time:
1. Decide what matters more: prestige or value.
If you want the most recognised name, go GIA.
If you want the best specs for your budget, IGI gives you more options.
2. Look at the diamond, not just the paper.
A perfect grading report doesn’t guarantee a beautiful stone.
Use your eyes. Trust your gut.
3. Don’t get stuck on tiny grading differences.
An F vs a G colour will never matter in real-life lighting.
4. Work with a jeweller who actually understands lab-grown.
This might be the most important one.
Not every jeweller is experienced with lab-grown diamonds, and not everyone understands the differences between IGI and GIA. Find someone who does.
Which One Should You Choose?
Here’s the truth I’ve learned after years of buying, comparing, and setting these stones into rings:
You can’t go wrong with either.
IGI and GIA are both reliable, internationally recognised, and highly trusted.
The better question is this:
Which report makes you feel more confident in your purchase?
Because buying a diamond — lab-grown or mined — is part logic, part emotion. And both deserve equal space in the decision.
A Final Thought From a Jeweller Who’s Seen It All
You know, the longer I work in this industry, the more I realise people aren’t really buying diamonds for their grading reports. They’re buying moments. Memories. Meaning.
Whether your stone carries an IGI report or a GIA report, it will shine in exactly the same way when you slide it onto someone’s finger.
What matters most is that you feel good about the choice — proud, excited, and maybe even a little emotional.
If the certification helps with that, wonderful.
If it’s the sparkle that grabs your heart, even better.
Just don’t forget: diamonds are small objects, but they hold huge stories.
And the one you choose becomes part of yours.