Diamonds

CIBJO U-Turn: Don’t Say Lab Grown, Say Synthetic

The World Jewellery Confederation (CIBJO) is set to reverse a decision made in 2010 – and insist that non-natural diamonds are labelled as “synthetic”.

It says the terms “laboratory-grown” and “laboratory-created” should be removed from the Diamond Blue Book – the de facto standard for diamond terminology, grading and trade practices – and from all relevant ISO Standards.

In addition, the 4Cs grading system should be used only for natural diamonds (as the GIA is now doing).

Udi Sheintal (pictured), president of CIBJO’s Diamond Commission, said the original acceptance of lab grown terminology had been well-intentioned, but proved to be misplaced.

“At the time, we believed we were acknowledging a commercial reality and extending a constructive hand to a new segment of the industry,” he said, in a special report ahead of the 2025 CIBJO Congress in Paris at the end of October.

“We hoped for a spirit of cooperation, with shared standards, ethics and transparency.”

But he said many in the synthetic diamond sector â€” along with some grading laboratories and major retail chains – took advantage of that inclusive approach.

“In addition, the marketing narrative around synthetic diamonds has been aggressively shaped to position them as the more ethical, sustainable, and conflict-free choice, almost always without substantiation.”

He also called for greater transparency, requiring that all descriptions and marketing of synthetic diamonds reflect the reality of their origin: they are not grown or created in a “laboratory,” but rather are manufactured in industrial facilities through artificial processes.

Source: IDEX

US Tariffs: Patek Philippe “to Hike Prices by 15%”

Patek Philippe will reportedly hike watch prices by 15 per cent tomorrow (Monday 15 September) in response to US reciprocal tariffs.

If confirmed, it will be Patek Philippe’s third price rise in the US this year, according to the WatchPro website.

Prices were increased in January because of soaring gold prices and the strength of the Swiss franc, and in April as a response to the US announcement of across-the-board tariffs.

Authorized dealers will also have their margins cut. Patek Philippe will be the first Swiss watchmaker to raise prices since the US introduced 39 per cent tariffs on 7 August.

Watchmakers rushed to export their goods ahead of the tariff deadline, resulting in a 6.9 per cent increase during July.

But price increases in the near future are almost inevitable as the reciprocal tariffs bite and stocks need replenishing.

One of the lowest-priced Patek Philippes, the $26,000 stainless steel Patek Philippe Aquanaut Ref. 5167A-001 (pictured) will cost $30,000 if the price increases take place.

Source: IDEX

Signet Sales Increase, Driven by Lab Growns

Signet reported increased sales for Q2, as consumers increasingly opted for lab growns over natural diamonds.

It said 14 per cent of all the fashion jewelry items it sold during the quarter were lab grown – twice as many as the same period last year, and higher than Signet’s own expectations.

Total sales for the 13 weeks to 2 August were $1.5bn, up 3.0 per cent, and same store sales increased by 2.0 per cent, Signet said in its Second Quarter Fiscal 2026 Results.

Kay, Zales, and Jared the retailer’s three largest brands together delivered a combined 5 per cent same-store sales growth.

Adjusted operating profit for the quarter rose over 20 per cent reaching $85m, with a 24 per cent year-over-year gain.

Lab growns are viewed as a “category extender for fashion” and demand is most prominent in lower-priced products and fashion jewelry.

“Our second quarter results were driven by the expansion of on-trend fashion assortment and effective promotion and pricing strategies,” said J.K. Symancyk, Signet’s CEO.

Joan Hilson, chief operating and financial officer, said: “Reflecting second quarter results, expectations for the third quarter, and current tariff landscape, we’re raising our Fiscal 2026 guidance.

“This updated guidance also includes share repurchases to date and assumes a measured consumer environment.”

Source: IDEX

Small Rise in US Watch and Jewelry Sales

The modest increase largely reflects a rush by exporters to get their goods into the US before the tariff deadlines and retailers stockpiling for the same reason.

It offsets low consumer demand, which is being compounded by ongoing anxiety over US reciprocal tariffs which are expected to force up prices.

Average monthly growth in watch and jewelry sales so far, for the first seven months of this year, has been around 0.6 per cent, compared to over 5 per cent last year.

Sales in June were down 0.9 per cent, a figure that has been revised up from the original -1.7 per cent, based on actual transactions rather than estimates.

Exports of Swiss watches were up 6.9 per cent, largely driven by manufacturers front-loading their shipments to avoid 39 per cent US tariffs.

Source: IDEX

HPHT-Processed Natural and Laboratory-Grown Diamonds with Counterfeit Inscriptions

Recently, the Dubai laboratory encountered four stones submitted for update services inscribed with fraudulent GIA report numbers. Inconsistent font styles and placement indicated the numbers were not authentic GIA inscriptions.

Table 1. Comparison of characteristics of submissions with counterfeit inscriptions and their accompanying GIA grading reports.
A careful comparison of their quality characteristics confirmed that these were not the same diamonds as described in their accompanying reports. Although the diamonds were carefully selected to closely match the features listed on the original reports, several subtle differences in their color grades, measurements, and other characteristics were identified (table 1). Even more obvious were the spectral differences between the fraudulent and original stones. The difference in the one-phonon region of the Fourier-transform infrared absorption spectroscopy clearly revealed a discrepancy in the diamond types. The diamonds from the original reports were type Ia with aggregated nitrogen impurities, while these submitted stones were all type IIa, confirming they were, in fact, different stones.

On fraudulent diamonds 1 and 2, photoluminescence (PL) spectra produced by 514 nm laser excitation at liquid-nitrogen temperature showed that 637 nm peaks were greater than 575 nm peaks. The 575 and 637 nm peaks are emissions from the nitrogen vacancy center in its neutral [NV]0 and negative [NV]− charge states, respectively. The 575:637 nm emission ratio of intensities of less than 1 (D. Fisher and R.A. Spits, “Spectroscopic evidence of GE POL HPHT-treated natural type IIa diamonds,” Spring 2000 G&G, pp. 42–49), along with other PL features, indicated that fraudulent diamonds 1 and 2 with the counterfeit inscriptions were natural diamonds that had undergone high-pressure, high-temperature (HPHT) treatment for color improvements.

The visible/near-infrared (Vis-NIR) absorption spectrum for fraudulent diamond 3, on the other hand, showed a 737 nm peak, which corresponds to the unresolved silicon vacancy [SiV]– defect at 736.6/736.9 nm commonly seen in laboratory-grown diamonds using the chemical vapor deposition (CVD) growth method (P. Martineau et al., “Identification of synthetic diamond grown using chemical vapor deposition (CVD),” Spring 2004 G&G, pp. 2–25). The observation of such features led to the determination that this stone was CVD-grown and subjected to post-grown HPHT processing.

Further PL spectroscopy analysis on fraudulent diamonds 3 and 4 using 633 nm excitation confirmed the presence of the SiV– doublet feature on both diamonds. In alignment with the Vis-NIR and PL spectra, DiamondView images of these two fraudulent stones displayed clear striations with interruption layers indicative of CVD growth (figure 1). These patterns are consistent with the step-flow growth structure of CVD-grown diamond, which was also visible under the microscope using crossed polarizers and further supported their laboratory-grown origins. The other two fraudulent diamonds (1 and 2), however, showed a lack of such patterns and demonstrated natural-looking features, which confirmed them as HPHT-processed natural diamonds.

Figure 2. GIA’s standard procedure is to cross out the counterfeit inscription. Image by GIA staff.
Figure 2. GIA’s standard procedure is to cross out the counterfeit inscription. Image by GIA staff.
Considering all evidence, we concluded that two of the four stones were laboratory-grown diamonds, and the other two were HPHT-processed natural diamonds. All four diamonds were not the same natural diamonds as described in their accompanying GIA grading reports. In accordance with GIA procedures, the counterfeit inscriptions were crossed out (figure 2) and new report numbers were assigned. In addition, GIA inscribes “TREATED COLOR” on natural diamonds with post-treatment history and “LABORATORY-GROWN” along with a GIA report number and distinct GIA LG logo on laboratory-grown diamonds.

Deceptive practices have occurred previously in the trade; similar instances of diamonds with fraudulent inscriptions have been reported by GIA (e.g., Summer 2021 Lab Notes, pp. 150–152; Fall 2021 Lab Notes, pp. 258–259). Additionally, non-diamond materials, such as synthetic moissanite, with fraudulent GIA inscriptions have been submitted as diamonds to GIA (Fall 2020 Lab Notes, pp. 424–425; Fall 2022 Lab Notes, pp. 360–361). These cases highlight the importance of verifying inscription authenticity because a fraudulent inscription could be overlooked by simple visual examination. One possible solution is GIA’s Match iD, a device that compares a diamond’s inscription with its grading report in the GIA database.

Source: GIA

Lucara Recovers Rare 37-Carat Pink Diamond from Karowe

Lucara Diamond Corp. has announced the recovery of a rare and unusual pink diamond from its Karowe mine in Botswana.

The 37.42-carat stone, classified as a Type IIa, was unearthed in August and is described as near-gem quality with a distinctive bicoloured appearance. While the majority of the diamond displays an intense pink hue, part of the stone appears partially colourless an exceptionally rare feature.

HB Antwerp, Lucara’s cutting and technology partner, described the discovery as “a rare and remarkable find.” Oded Mansori, co-founder of HB Antwerp, noted:
“This stone has the potential to become one of the most important pink diamonds ever polished. Its intensely rich coloration is a testament to the geological uniqueness of the Karowe mine, and our expertise in the manufacturing process will ensure its vibrant colour is maximised.”

The recovery underscores Karowe’s reputation as a consistent source of exceptional diamonds. Also in August, Lucara recovered a 1,019.85-carat non-gem-quality diamond, the third stone of more than 1,000 carats to be found at Karowe in 2025. This brings the total number of diamonds over 1,000 carats from the mine to nine.

Both diamonds were recovered from the EM/PK(S) section of the deposit using Lucara’s Mega Diamond Recovery (MDR) unit, an advanced X-ray transmission system installed in 2017 to identify and preserve large stones. The MDR is credited with detecting several of Karowe’s most significant recoveries, including the 2,492-carat diamond discovered in August 2024—the second-largest rough diamond ever found.

Meanwhile, Lucara has announced a $10 million drawdown from its $63 million standby loan facility with Nemesia, its largest shareholder, to address short-term funding needs for the Karowe underground expansion project. The $683 million project, now scheduled for completion in the first half of 2028, is expected to extend the mine’s life to at least 2040.

Lucara President and CEO William Lamb said the arrangement reflects the company’s commitment to financial prudence while advancing the underground project.
“This funding mechanism demonstrates the continued confidence and support of our major shareholders in Lucara’s long-term strategy and in the exceptional value potential of the Karowe mine, including the ongoing recovery of some of the world’s most significant diamonds.”

Sotheby’s to Sell 31.86 carat Pink Diamond in Abu Dhabi

Sotheby’s is to offer for sale the largest fancy vivid orangy pink diamond ever graded, at a debut event in Abu Dhabi in December.

The pear-shaped gem, known as the Desert Rose, weighs 31.86 carats and is expected to fetch $5m to $7m.

It is the jewelry highlight of Sotheby’s inaugural Abu Dhabi Collectors’ Week of exhibitions, sales, masterclasses and panel discussions.

The Desert Rose is part of a single-owner collection of watches and jewelry, including vintage and contemporary signed pieces, that is estimated to raise more than $20m in total.

Among the watch highlights is an exceptionally rare Rolex “Oyster Albino” Daytona, reference 6263, produced in the late 1960s and early 1970s, with an estimate of $500,000 to $1m.

Abu Dhabi Collectors’ Week takes place from 2 – 5 December on Saadiyat Island, just off the Abu Dhabi coast.

It coincides with the Abu Dhabi Grand Prix and features auctions of collector cars, real estate, and international fine art exhibitions.

Source: IDEX

Lab Grown Diamond Market to Hit $44bn

The global lab grown diamond market will grow 60 per cent in the next seven years, from $27.7bn this year to $44.5bn in 2032, according to India-based Coherent Market Insights (CMI).

That represents a compound annual growth rate (CAGR) of 7 per cent annually. It did not provide comparable figures for the natural diamond market, although growth there is expected to be considerably slower.

The CMI report identifies North America as the current market leader, expected to capture roughly 40% of global demand in 2025.

However, it says the Asia-Pacific region, which currently accounts for 40 per cent of lab grown sales, is projected to experience the fastest growth, driven by rapid industrialization and increasing disposable incomes.

China is the biggest producer – accounting for almost half of global production – but most is by HPHT, an older and less sophisticated system than CVD.

Source: IDEX

What Is a Diamond Culet?

The culet is the tiny facet at the very bottom of a diamond’s pavilion.

When looking closely at a diamond’s cut, one feature that often goes unnoticed is the culet. Though small, this detail plays a role in both the durability and the overall appearance of a stone.

Defining the Culet

The culet is the tiny facet at the very bottom of a diamond’s pavilion. Traditionally, it was cut to protect the fragile tip of the diamond from chipping or damage. In modern cutting, many diamonds are fashioned with either a very small culet or none at all, creating what appears to be a sharp point.

When viewed under magnification, a culet may look like a small circle in the centre of the diamond’s table (the flat top surface). Grading reports will often describe it using terms such as “None,” “Very Small,” “Small,” or “Medium.”

The Purpose of the Culet

Durability: The culet prevents the diamond’s pointed tip from breaking during setting or daily wear.

Light Performance: A well-proportioned culet has little to no effect on brilliance, but if the culet is too large, it can be visible through the table, appearing as a dark spot.

Aesthetic Tradition: Older cuts, such as Old European or Old Mine cuts, often feature larger culets, which are considered a hallmark of antique diamonds.

What if the Diamond Has No Point at the Bottom?

In modern cutting, some diamonds are designed without a defined point or traditional culet at the base. Instead of tapering to a sharp tip, the pavilion may finish with a flattened surface or an elongated structure.

This is sometimes informally described as a linear culet—a feature where the bottom of the stone forms a line or edge rather than a point.

Linear Culet – Not Standard Terminology

It’s important to note that “linear culet” is not a recognised term in official diamond grading systems. Laboratories such as GIA (Gemological Institute of America) or DCLA (Diamond Certification Laboratory of Australia) will not use this terminology on grading reports. Instead, they simply describe the culet as “None,” “Pointed,” or with size descriptors.

However, for a novice jeweller and clients, the term linear culet can be a helpful way of communicating what the eye perceives — especially in cases where the diamond clearly does not come to a point. Using this descriptive language provides clarity in conversation, even if it doesn’t appear on formal certificates.

Conclusion

The culet may be one of the smallest aspects of a diamond, but it reflects both the stone’s cutting tradition and the cutter’s intention to balance brilliance with durability. Whether pointed, open, or even described informally as linear, the culet is a fascinating detail that connects modern diamonds with centuries of cutting history.

GIA to Ditch 4Cs Lab Grown Grading from October

GIA says the switch to grading lab grown diamonds simply as “premium” or “standard” will take on 1 October.

The lab announced an end to full 4Cs color and clarity reports in June, but did not say at the time when the change would take effect.

In a statement yesterday (26 August) it also laid out the criteria it will use to distinguish Premium lab growns from Standard. Diamond that don’t meet all the minimum criteria for Standard will not receive a GIA assessment.

Premium diamonds must meet all these criteria:

Clarity – Very, Very Slightly included and higher
Color – D
Polish, symmetry – Excellent
Cut grade – Excellent (round brilliant cut diamonds only)

Standard diamonds must meet all these criteria:

Clarity – Very Slightly included
Color – E-to-J
Polish – Very Good
Symmetry – Very Good (or Good for fancy shapes)
Cut grade – Very Good (round brilliant cut diamonds only)

GIA will charge $15 per carat, with a minimum fee of $15. Evaluation fee for diamonds below the minimum criteria is $15.

“Using descriptive terms for the quality of laboratory-grown diamonds is appropriate as most fall into a very narrow range of color and clarity,” said Pritesh Patel, GIA president and CEO.

“Because of that, GIA will no longer use the nomenclature created for natural diamonds to describe what is a manufactured product.”

Meanwhile rival lab IGI (International Gemological Institute) insists it will carry on with 4Cs grading for lab growns “to prevent industry and consumer confusion”.

Source: IDEX