Lab-grown diamonds are indistinguishable from natural ones to the naked eye—but the difference can make or break your business. Here’s why proper screening isn’t optional anymore.
As the gap in value between lab-grown and natural diamonds widens, the jewellery industry faces a growing risk: the misidentification and misrepresentation of diamonds. Whether due to fraud or unintentional oversight, the presence of synthetic diamonds in parcels sold as natural is increasing—damaging trust, reputations, and potentially entire businesses.
In recent years, organisations like GIA have discovered lab-grown diamonds intentionally cut to match natural stones—including falsified GIA report numbers etched onto their girdles. And that’s just the tip of the iceberg. The problem now extends beyond bad actors to well-meaning retailers who simply lack the proper screening equipment or expertise to verify every diamond they sell.
Lab-Grown Diamonds: A Rising Threat to Retail Integrity
Let’s be clear: lab-grown diamonds are not inherently problematic. They are legitimate products with growing popularity among budget-conscious buyers. The problem lies in misidentification—when a lab-grown diamond is presented or sold as natural, either intentionally or by mistake.
Unfortunately, many retailers sell natural, lab-grown diamonds and even moissanite from the same premises without having invested in screening technology. Without strict protocols and accurate testing, even experienced jewellers are effectively “flying blind”—forced to trust suppliers or visual inspections that are no longer sufficient.
What Happens When Diamonds Are Misidentified?
The consequences of diamond misidentification can be catastrophic—not just for the buyer, but for the entire industry.
Imagine a client purchases what they believe is a natural diamond, only to find out—years later during resale or insurance valuation—that it’s lab-grown and worth far less than expected. The damage to consumer trust is immediate and long-lasting. In the eyes of that customer, all jewellers become suspect.
Even worse, retailers unknowingly issuing inaccurate valuation certificates risk legal consequences and reputational ruin. This is especially concerning given the widespread industry practice of providing insurance valuations. Without screening tools, many certificates may already be incorrect—describing synthetic stones as natural ones.
A Legal and Ethical Obligation
The Jewellery Council of South Africa (JCSA) is clear: anyone who sells diamonds must accurately describe what they sell. If you market an item as a “diamond bracelet,” it must not include lab-grown stones. If it does, that fact must be clearly stated. The same applies to any valuation or sales document: the word “diamond” implies natural, unless otherwise specified.
This isn’t just ethical—it’s the law. Yet many local jewellers continue to operate without the tools needed to fulfil this obligation.
Lab-Grown Screening: An Investment in Trust
Let’s talk numbers. Many jewellers buy and sell diamond jewellery worth millions of rands annually. But when it comes to protecting that investment with a proper synthetic diamond screener, they hesitate to spend R150,000–R200,000.
Viewed as a long-term investment, this is a small price to pay. Equipment depreciation, tax deductions, and most importantly—consumer trust—far outweigh the upfront cost. Retailers who don’t screen risk selling undervalued stock or, worse, damaging the entire industry’s credibility.
At Prins & Prins, we’ve used the GIA i100 synthetic diamond screener for years to ensure every diamond we buy, sell, or value is accurately identified. Our internal process includes weighing the stone, testing with a thermal conductometer (to rule out glass, moissanite, and CZ), and then screening for natural vs lab-grown characteristics.
In fact, we’ve returned stones to suppliers that didn’t pass our tests—and to their credit, they replaced them with natural stones without issue. But this only works if you’re screening in the first place.
A Looming Valuation Crisis
The situation is reaching a tipping point. Insurance companies are likely to demand third-party certification—from recognised gem labs—for jewellery valuations in the near future. Why? Because without lab-grown screening tools, most retail valuations are unreliable.
If this shift happens, retailers who cannot certify their stones will be excluded from the valuation process—potentially losing clients and credibility in the process.
The Case for Shared Screening Services
We understand that not every retailer can afford a screener today. That’s why accessible screening facilities in major cities are urgently needed. Whether offered by the SA Jewellery Council or a savvy entrepreneur, same-day screening services could help retailers stay compliant and protect their reputations.
These services could combine synthetic diamond testing with precious metal analysis using XRF analyzers, giving jewellers a full picture of their inventory at an affordable rate.
What Screening Equipment Should You Buy?
If you’re considering a screening device, consult the Natural Diamond Council’s Assure Program, which tests and rates screening instruments based on accuracy, features, and reliability. Remember that most devices are screeners, not detectors—meaning they can flag suspicious stones, but some natural diamonds (~4–5%) may still require advanced lab confirmation.
Still, having a screener puts you miles ahead of most unprepared retailers—and your customers will thank you for it.
Final Thoughts: Your Reputation Is Priceless
Your business isn’t just about diamonds—it’s about trust. Every misidentified stone, every faulty valuation, and every disappointed client chips away at your brand. With the influx of lab-grown diamonds into the market, retailers can no longer afford to guess. You must know what you’re selling.
Spending R200,000 on a reliable screener may seem steep—but compared to the cost of a ruined reputation, it’s a bargain.
About the Author
Dr. Petre Prins is a renowned gemmologist and founder of Prins & Prins Diamonds in Cape Town. With decades of experience in gem testing, jewellery valuation, and diamond certification, he advocates for ethical practices and scientific precision in the jewellery industry.
📍 Visit Prins & Prins for expert diamond valuations and natural gemstone certification you can trust.
