Are Gemstones a worthy investment? The expert guide to Burmese rubies, Kashmir Sapphires, and beyond…

For centuries, precious stones have captivated humanity — not merely as adornments, but as portable, enduring stores of wealth. Kings concealed rubies in the lining of their robes. Maharajas traded emeralds the size of plums. And today, a collector in London can acquire a Kashmir sapphire without leaving their kitchen table.

But the democratisation of the gem trade has brought with it a dangerous abundance of noise. Scroll through social media on any given day and you will encounter dealers and brokers making sweeping declarations: "Buy a Burmese ruby — they're rarer than diamonds, and the price only goes one way", or "This Kashmir sapphire is an instant investment, these stones are impossible to find now." These are the kinds of claims that circulate with confidence and without context. The first may well be true of a specific, certified, unheated stone of fine quality — and almost entirely untrue of a heated commercial-grade ruby bought at a gemstone trade fair.

The truth is far more nuanced — and far more interesting.


The Market Is Driven by Forces Most Buyers Never Consider.

Gemstone pricing does not exist in a vacuum. Geopolitics, civil conflict, currency collapse and supply chain disruption all exert a profound and often underestimated influence on what a stone will fetch on any given day. For anyone seriously considering investment gemstones, understanding these forces is not optional — it is foundational.

Two examples illustrate this vividly.

In 2022, Sri Lanka was engulfed by its worst economic crisis since independence. The movement known as the Aragalaya — meaning "struggle" in Sinhala — saw mass protests topple the government as the country defaulted on its national debt, fuel ran dry, and the rupee collapsed in value. The effects rippled directly into the island's legendary gem trade. Sri Lanka is the world's most prolific source of fine sapphires, and as economic paralysis gripped the country, supply to international markets tightened sharply. Dealers who had lent stones on consignment pulled them back; the costs of mining skyrocketed, and miners held their stocks rather than sell into a collapsing currency. The result was a meaningful upward pressure on Sri Lankan sapphire prices in international markets that persisted well into 2023, and the effects of which still ripple today

Myanmar's military coup in February 2021 told a similar story. As the kyat went into freefall, citizens and gem traders alike turned to what they knew held real value: rubies, sapphires, and spinels from the legendary mines of Mogok. Stones that might otherwise have entered the international market were held back, tightening supply and pushing prices for fine-quality Burma rubies and other Burmese gems sharply higher in the months that followed.

These are not textbook scenarios. They are the lived reality of a market that, for all its glamour, operates on the same cold logic as any other commodity.


Start With the Fundamentals: The Four Cs

Every conversation about gem quality begins in the same place: the four Cs — carat, cut, colour, and clarity. These are the universal benchmarks established by the Gemological Institute of America (GIA) and adopted as standard across the industry.

For a stone to be considered an investment gemstone, it must perform well across all four criteria — though not all carry equal weight in every context.

Cut must be excellent. A poorly cut stone haemorrhages light and value in equal measure. Colour and clarity are paramount: investment-grade gems occupy the upper echelons of their respective grading scales, free from visible inclusions and displaying the kind of saturated, vivid hue that makes a stone immediately arresting to the eye. In the case of sapphires, that means the deep, velvety tone the trade refers to as royal blue — a quality associated above all with the finest Kashmir and Burmese specimens.

Carat weight is the variable most buyers fixate on, though it is arguably the least decisive in isolation. That said, most serious gem dealers would agree that a minimum of one carat is a sensible baseline. Beyond that threshold, rarity increases exponentially with size — a two-carat unheated Burma ruby of fine quality is not simply twice as rare as a one-carat equivalent; it is many times rarer, and priced accordingly.


Provenance and Treatment: The Twin Pillars of Investment Value

Beyond the four Cs, two further variables define whether a gem is truly investment-grade: where it comes from and whether it has been treated. These two factors carry roughly equal weight, and neither can be considered in isolation from the other. A stone with impeccable provenance that has been treated loses much of its premium; an untreated stone of uncertain or unremarkable origin may still fall short of investment grade. It is the combination of both that elevates a gem into a category of its own.

Provenance: The Power of Origin

Certain mining regions have, over decades and centuries, produced gems of such consistent quality and distinctive character that their names have become synonymous with excellence — and command prices to match.

Burma rubies from the Mogok Valley remain the undisputed gold standard of the ruby world. Prized for their extraordinary "pigeon's blood" colour — a rich, vivid red with a natural red fluorescence that makes the stone appear to glow — a fine, unheated Burma ruby with a credible laboratory certificate is among the most sought-after objects in the entire gem market. Supply is finite and diminishing; demand is not.

Kashmir sapphires occupy the same rarefied space in the sapphire world. Mined in a remote and largely inaccessible region of the Himalayas at altitudes above 4,500 metres, these stones are distinguished by their velvety, royal blue hue — a quality that no other origin has been able to consistently replicate. The original deposits are now essentially exhausted, meaning that verified, fine-quality Kashmir sapphires are among the scarcest objects in the gem trade. When examples appear at auction, they routinely set records.

Colombian emeralds, particularly those from the Muzo and Chivor mines, are considered the finest in the world, their vivid green saturation unmatched by stones from Zambia or Brazil, which — while often beautiful — trade at a meaningful discount by comparison.

One critical caveat, however: origin alone does not make a stone an investment. A mediocre Kashmir sapphire will not outperform a truly exceptional specimen from Sri Lanka. The stone's individual qualities must always be weighed alongside its provenance — never subordinated to it.

Treatment: The Factor That Can Transform — or Destroy — Value

It is important to state clearly at the outset: heat treatment is not a dirty word. It is a centuries-old, universally accepted practice within the gem trade, and there is no stigma whatsoever attached to owning a heated stone. The process — exposing rough gems to controlled high temperatures to enhance colour and clarity — is so standard that it is effectively the industry default. According to gemological estimates, approximately 95% of all sapphires on the market today have been heat treated, and the figure for rubies is, if anything, higher still, with some estimates suggesting that far less than one percent of gem-quality rubies reach the market in a completely untreated state. When you buy a sapphire or ruby without specifically seeking out an untreated stone, the near-certainty is that it has been heated. That is not a flaw. It is simply the reality of the market.

Other treatments, however, occupy a different tier of consideration entirely. Fracture filling, beryllium diffusion, and lead-glass filling are more invasive interventions that alter the fundamental structure of a stone rather than simply optimising what nature has already produced. Oiling — common in the emerald trade — falls somewhere in between, and is graded on a scale from "minor" to "significant" by the major laboratories. These treatments are more consequential to value and require fuller disclosure.

So why does the heated versus unheated distinction matter so much in an investment context? Precisely because heating is so universal, a stone that achieves fine colour and clarity entirely without it is demonstrably, verifiably rare — and rarity, in the gem world, is the engine of value.

This is precisely why unheated gemstones command such a significant premium. A no heat ruby or no heat sapphire — one that has emerged from the earth and reached the market entirely in its natural state, without any artificial enhancement — is a genuinely rare object. In the top tier of the market, the difference in value between a heated and an unheated stone of otherwise identical quality can be substantial, often running to several multiples of price.

For investment purposes, unheated, untreated gems are almost always the only category worth serious consideration. A fine no heat Kashmir sapphire of royal blue colour, for example, represents one of the most compelling investment propositions in the entire gemstone market — combining the scarcity of the origin with the additional rarity of being entirely natural.


Certification: Essential, But Never a Substitute for Seeing the Stone

An investment-grade gem must be accompanied by a certificate from an internationally recognised, independent gemological laboratory. The leading names in the field — the GIA (Gemological Institute of America), Gübelin, SSEF, and GRS (Gem Research Swisslab) — are widely regarded as the gold standard, and their reports carry genuine weight in the international market. For Burmese rubies and Kashmir sapphires in particular, a certificate confirming both origin and the absence of heat treatment is not a formality: it is what makes the stone sellable to a serious collector or at a major auction house.

However — and this point cannot be overstated — a certificate is never a substitute for examining the stone itself. A certificate describes a gem as it was assessed at a point in time. It cannot tell you how the stone looks in the hand, how its colour performs in different lighting, or whether it has any number of inclusions that will have a major influence on its value or saleability. No serious buyer should ever purchase an investment gemstone on the strength of paperwork alone, without first having the stone independently assessed by a trusted expert. Certificates matter enormously; they are not, however, the whole picture.


The Verdict

There is no such thing as a guaranteed return in the gem market, and anyone who tells you otherwise should be treated with the same scepticism you would apply to a stockbroker promising certain profits.

What can be said, with confidence, is this: a select category of gemstones — fine quality unheated Burmese rubies, Kashmir sapphires of cornflower, or royal blue colour, and fine Colombian emeralds among them — has shown a consistent and compelling track record of appreciation over five, ten, and twenty-year periods. Certain categories within this already rarified world have more than doubled in value within a decade.

The flip side is equally true. The market is littered with stones that have been positioned as investment gemstones and delivered nothing of the sort. Due diligence is not optional. Finding a trusted, independent expert — one who works with your best interests in mind — is, for most buyers, the essential first step.

Treat it as you would any serious investment: with patience, rigour, and a healthy respect for what you don't yet know.