Monthly Diamond Market Update – May 2025

Welcome to our monthly column dedicated to the diamond market. Each month, we analyze the key global trends, significant events, and dynamics that impact demand, prices, and business strategies. With authoritative sources like Rapaport News, IDEX, and other specialized channels, we provide you with an up-to-date and reliable overview.

Overall Market Overview

May 2025 ended in a standstill, with mixed signals: on one hand, retail demand, particularly in the United States, remained stable; on the other hand, prices resumed their decline after a brief and modest increase in April. The international IDEX index, which tracks the prices of cut diamonds, reported a decrease of 1.37% compared to the previous month, confirming a downward trend that has been ongoing for over two years. The RAPI™ index, one of the main benchmarks in the industry, remained largely unchanged for 1-carat diamonds. Smaller diamonds and those with special cuts (such as emerald, marquise, and oval cuts) faced more challenges, while high-quality stones above 3 carats held up better. The sector continues to move with great caution, awaiting clearer signals from the international market.

A detailed analysis of the IDEX price lists shows a fluctuating trend: some segments have recorded slight increases, but in most categories, especially for fancy diamonds and medium-small stones, prices are on the decline.

Key Events of May 2025

• The trade tensions between the United States and India, key players in the diamond supply chain, seem to have eased temporarily, as the imposition of new tariffs has been postponed for 90 days. This news provided some relief to operators, but uncertainty remains high, especially for those exporting to the U.S.
• In Europe, interest in diamonds as investment assets remains lukewarm. Italian and French jewelers are receiving an increasing number of requests for appraisals and sales, while purchases of new jewelry are stagnating. The situation is further exacerbated by the growing competition from synthetic diamonds, which particularly attract younger consumers.
• The GemGenève fair, one of the most important events for the industry in Europe, closed in mid-May with strong results for high-end diamonds, particularly those over 5 carats. However, attendance was lower compared to the years before the Covid pandemic, indicating that the market has not fully recovered.
• On May 8th, De Beers, the historic leader in diamond mining and sales, announced the permanent closure of Lightbox, its synthetic diamond brand launched in 2018. This decision, which surprised industry players, was made following a 90% collapse in the wholesale prices of synthetic diamonds and marks a clear return to the natural diamond business. In the meantime, rumors are circulating about underpriced sales of rough diamonds to selected clients.

Curiosities from the Diamond World

A Revolution in Islamic Finance Comes from Diamonds

Diamond Standard, an American company specializing in the creation of "bars" and "coins" containing standardized diamonds, has received approval to use diamonds in Islamic finance. But what exactly does this mean?

Islamic finance follows the principles of Sharia, the Muslim religious law, which prohibits lending money for interest. Instead of traditional loans, Islamic banks use transactions backed by physical assets, such as metals (nickel, copper, aluminum), which, however, are bulky and expensive to transport and store.

This is where diamonds come into play: they have a very high value in a minimal volume, which drastically reduces management costs. In practice, instead of shipping tons of copper to secure a transaction, only a handful of diamonds are needed.

The true innovation lies in the fact that Diamond Standard has made diamonds "standardized," meaning they are selected and combined in such a way that they always have a recognizable, certified, and easily tradable value, much like gold bars. Each set is verified by independent entities and registered on blockchain, allowing them to be treated as a true financial asset.

The company has already created a commercial entity in the Gulf with an initial capital of $280 million and has chosen Dubai, which does not impose customs taxes, as its operational base.

This is yet another surprising use that diamonds are finding in the modern era. This innovation could revolutionize a billion-dollar market, making diamonds not only precious stones to flaunt but also sophisticated financial instruments in line with the principles of the Islamic faith.

India Blocks the Piprahwa Jewelry Auction: A Treasure Contested Between the Sacred and the Profane

This is a story with all the elements of an international thriller: ancient treasures, colonial legacies, legal battles, and matters of faith. On May 7, 2025, just hours before the start of the Sotheby’s auction in Hong Kong, the Indian government managed to secure a postponement of the sale of the Piprahwa jewelry, a collection of 334 sacred gems valued at an estimated $13 million.

But why are these jewels in Hong Kong? The answer takes us back to 1898, when William Claxton Peppé, a British engineer managing large estates in northern India, decided to excavate a mysterious hill on his property near the Nepalese border. The famine of 1896-97 had devastated the region, and Peppé organized the excavation to provide work for starving farmers.

What he found surpassed all imagination: after digging through 5.5 meters of masonry, Peppé discovered a massive stone chest containing five jars with over 1,800 pearls, rubies, topaz, sapphires, and gold leaf, along with bone fragments and ashes. But the real twist came when an inscription revealed that it contained the relics of the Buddha. Peppé had uncovered a stupa, a Buddhist funerary monument in the shape of a dome, which held both the bodily remains and votive objects of the Buddha after his cremation in 480 B.C.

The British Crown claimed the discovery under the Indian Treasure Trove Act of 1878. The bone fragments and ashes were donated to the Buddhist king of Siam (now Thailand), while most of the gems ended up in the Calcutta museum. However, Peppé was allowed to keep about a fifth of the gems, described as "duplicates."

These jewels remained in the Peppé family for over a century, eventually passing to Chris Peppé, a Los Angeles-based filmmaker and great-grandson of William. In recent years, the Peppé family has lent the gems to museums around the world, from the Metropolitan Museum of Art in New York to the National Museum of Korea in Seoul.

The decision to auction the jewelry in Hong Kong, a strategic hub for Asian art trade, sparked an uproar. The Indian Ministry of Culture sent a legal notice, claiming that the sale violated cultural heritage protection laws and accusing Sotheby’s of "participating in the ongoing colonial exploitation," as well as stating that the sale "offends the sentiments of over 500 million Buddhists worldwide."

The battle was successful, at least for now: Sotheby’s postponed the auction "to allow for discussions between the parties," leaving the fate of these sacred treasures hanging in the balance.

This Month's Analysis

Engagement Rings in 2025: A Quiet Revolution

The world of engagement rings is undergoing a monumental transformation that is redefining not only the aesthetic choices of couples but also the values underlying one of humanity's oldest traditions. We are witnessing changes that, just a few years ago, would have been unthinkable, driven by a generation that prioritizes sustainability, economic affordability, and personalization.

The most striking revolution undoubtedly concerns synthetic diamonds. According to the "Real Weddings 2025" study conducted on 17,000 American couples, 52% of engagement rings purchased in 2024 featured a synthetic diamond, compared to 12% in 2019—an increase of 40% in just five years, highlighting a profound generational shift. This trend is even more pronounced among Millennials and Generation X (born between 1980 and 2010), where the percentage exceeds 60%.

The numbers tell a clear story: while a natural 1-carat diamond typically costs around €3,600, its synthetic equivalent can be bought for €780. This price difference, which can reach up to 90%, allows couples to purchase significantly larger stones. Not surprisingly, one-third of consumers in 2024 chose rings over 2 carats, a 10% increase compared to pre-pandemic levels.

However, economic affordability is not the only factor driving this change. New generations are increasingly sensitive to ethical and environmental issues. Synthetic diamonds eliminate concerns related to mining practices and "blood diamonds," offering an alternative that does not compromise the beauty or quality of the stone. Industry analyst Paul Zimnisky predicts that by 2026, synthetic diamond sales will surpass those of natural stones in engagement rings.

From a stylistic perspective, 2025 marks the return of seemingly contrasting trends that reflect the modern couple's desire for personalization. On one hand, we are witnessing the resurgence of minimalism with solitaire rings, which have gained 10% popularity in recent years. On the other hand, there is a growing demand for statement rings with wider bands, settings that completely encase the stone, and the vintage allure of antique cuts, such as the old cushion cut and the historic European round brilliant cut.

A particularly interesting trend is the rise of rings with horizontal settings, where the stone is set horizontally rather than vertically. This style exploded after Zendaya showcased her stunning engagement ring at the latest Golden Globes: a cushion cut mounted horizontally on a classic band, a gift from Tom Holland. The ring went viral on social media, sparking a craze for this unconventional yet incredibly elegant style.

Selena Gomez has also helped set trends for 2025 with her customized engagement ring: an antique marquise-cut diamond set on a thick rose gold band with small diamonds embedded. The choice of the marquise cut, once considered outdated, is experiencing a revival, thanks in part to these celebrity influences.

At the same time, the popularity of three-stone settings is growing, symbolizing the past, present, and future of the relationship.

Platinum maintains its position as a premium metal, valued for its durability and prestige, but yellow gold is experiencing a significant resurgence, chosen by 31% of couples in 2024, up 15% from 2019. This return to warm tones reflects the desire to stand out from the classic white metals that have dominated the market for decades.

There are also bolder innovations: synthetic diamonds in pink, blue, and yellow are attracting couples who want to break completely with tradition, while interest in alternative stones such as moissanite is growing, with 40% of younger couples opting for stones other than diamonds.

The global diamond jewelry market, valued at $358 billion in 2024, is expected to grow to $437 billion by 2030. However, behind this growth lies a completely different scenario compared to the past: while natural diamonds maintain their prestige in the luxury segments, synthetics dominate the mass-market engagement ring sector.

This quiet revolution is not just a shift in aesthetic preferences but reflects a deeper cultural transformation. New generations are redefining what luxury and value mean, prioritizing accessibility, ethics, and personalization over traditional conventions. Engagement rings in 2025 are no longer just symbols of status, but expressions of shared values and conscious choices that will accompany couples into their future together.

Conclusions

May 2025 confirmed the uncertainties that still characterize the diamond market: falling prices or, at best, stable ones, limited demand, increasing competition from synthetic diamonds, and geopolitical tensions that are affecting the global dynamics of the supply chain. However, alongside these challenges, signs of positive transformation are also emerging: innovative new uses of diamonds in finance, growing consumer attention to ethical issues, and increasingly personalized and creative trends in the jewelry sector.

In this changing landscape, properly appraising your diamonds and jewelry has never been more important. Whether you're selling to fund a new project, settle a debt, or peacefully close a chapter of your life, knowing the true value of your diamonds is the first step. And to do this, it's essential to rely on serious, independent, and transparent experts.

With Auctentic, you can request a free, discreet, and no-obligation appraisal of your diamonds and jewelry. Our team will guide you step by step, with transparency and professionalism, to help you make the right decision at the right time.

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