Historical Diamond Market Trends: How Value Has Shifted Over Time

Key takeaway: The diamond market has moved through distinct eras, from scarce ancient supply, to the South African boom of the late 1800s, to tightly controlled mid-century pricing and today’s mix of natural and lab-grown stones. Understanding these shifts helps you read what your diamond is really worth.

Diamonds carry a reputation for permanence, yet the market around them has never stood still. Over the centuries the price of a diamond has been shaped by where they were found, who controlled supply, how marketing taught the public to value them, and most recently by laboratory-grown competition. If you own a diamond ring, a loose stone or an inherited piece and you are thinking about selling, the history of this market is not just trivia. It explains why two stones of similar size can carry very different value, and why timing and an honest valuation matter.

At The Gold Avenue in Illovo, Sandton, we buy diamond jewellery every week, and the questions people ask almost always trace back to these long market trends. Here is how the diamond market has evolved, and what that means for anyone weighing up a sale in Johannesburg.

The early diamond trade: scarcity set the tone

For most of recorded history, diamonds were genuinely rare. The earliest known sources were the riverbeds of India, where stones were gathered rather than mined at scale. Supply was small, distribution was limited to the wealthy and the royal, and that scarcity gave diamonds their first reputation as objects of power and status.

Because so few stones reached the market, value rested almost entirely on rarity and on the prestige of ownership. The modern grading language of cut, colour, clarity and carat had not yet been formalised. A diamond was prized simply because almost no one could obtain one. That foundation of scarcity still echoes in how the public perceives diamonds today, even though the supply picture changed dramatically later on.

The South African discovery that reshaped the market

The single biggest turning point in diamond history happened on South African soil. The discoveries in the Northern Cape in the second half of the 1800s opened up volumes of rough diamonds the world had never seen. What had been a trickle from Indian and Brazilian sources became a flood from the new South African fields.

This created a paradox. More diamonds reaching the market should, in theory, have pushed prices down. A flooded market threatened the very scarcity that gave diamonds their worth. The response to that threat shaped the next century of diamond pricing, and it is the reason South Africa sits at the centre of any honest history of the trade.

Why supply control became the story

Once large volumes were available, the people who controlled the mines understood that releasing every stone at once would collapse the price. The logical commercial move was to manage how many diamonds reached buyers and when. That instinct, to protect value by managing supply, became the defining feature of the market for generations.

The rise of De Beers and a controlled market

De Beers, founded in 1888 by Cecil Rhodes, grew into the organisation most associated with this supply management. By consolidating mines and channelling rough diamonds through a central selling system, the company was able to influence how much reached the market and at what price. For a long stretch of the twentieth century, this gave the diamond price a stability that few other commodities enjoyed.

The other half of the strategy was demand. The famous line “a diamond is forever” did more than sell engagement rings. It taught the public that a diamond was a permanent, emotional purchase that should never be resold casually. That idea was brilliant marketing, and it is worth understanding clearly if you are a seller, because it deliberately discouraged a strong secondhand culture. The result is that many owners never learned how the resale side of the market actually works.

The twentieth century: stability, then fluctuation

Through much of the 1900s, controlled supply and powerful marketing kept the diamond market remarkably orderly. Prices tended to rise steadily, and diamonds gained a reputation as a store of value alongside their emotional appeal. For sellers, this was the era that built the assumption that a diamond would always hold or grow its worth.

Towards the later decades, that tidy picture began to fray. Economic cycles, shifting consumer tastes and the growing complexity of the global trade introduced more movement into prices. The market was no longer a single steady line upward. It started to behave more like other markets, with periods of strength and periods of softness, and that variability is something every modern seller should keep in mind.

New producers break the old order

The mid to late twentieth century saw major new diamond sources come online outside the old South African heartland. Russia’s ALROSA became one of the largest producers in the world, while Australia’s Argyle mine added significant volume and became known for certain coloured diamonds. Canada later emerged as another important source.

The arrival of these producers gradually loosened the tight, single-channel control that had defined the market for decades. More players meant more independent supply and more competitive pressure. For consumers and sellers, this eventually meant a market that was broader, more transparent and less dependent on one dominant gatekeeper than it had been at its peak.

The diamond market today: natural and lab-grown

The most significant recent shift is the rise of laboratory-grown diamonds. These are chemically and physically diamonds, produced in controlled conditions rather than mined. They have grown from a niche curiosity into a meaningful share of the jewellery market, and they have changed the conversation about value.

For sellers this matters enormously. A natural diamond and a lab-grown diamond can look identical to the naked eye, yet they sit in very different value categories on the resale market. This is one of the main reasons professional testing is essential before any sale. Online research alone cannot tell you which type you are holding, and assuming the wrong one can cost you. The modern market rewards owners who get a stone properly assessed rather than relying on the receipt or family memory of what was bought.

What the trends mean for value now

• Natural diamonds still command a premium, but the price is influenced by the full picture of cut, colour, clarity, carat and condition, not size alone.
• Lab-grown stones generally carry different resale economics, so identifying the type accurately is the first job in any valuation.
• The wider field of producers means the market is more transparent than in the era of single-channel control, which favours sellers who shop their offer.
• Live market conditions move, so a valuation reflects the current market rather than the figure on an old appraisal certificate.

Selling a diamond in Johannesburg with The Gold Avenue

The long history above leads to one practical point. The value of a diamond is set by the market, by the stone’s own characteristics and by honest testing, not by the price it was once bought for. At The Gold Avenue we built our business in Illovo, Sandton, to give Gauteng sellers a transparent, five-star alternative to the old pawn-and-gold-buying trade, where the offer is explained rather than hidden.

When you bring a diamond piece to us, the process is straightforward:

1. Contact our team by phone, WhatsApp or online chat to start the conversation.
2. Book a valuation at our Illovo premises at a time that suits you.
3. Receive an offer after your jewellery is weighed, tested and assessed, priced on current market conditions and the condition of the piece.
4. Get paid the same day by cash or EFT once you accept.

Because we work with an international dealer network, particularly in the UAE, we are often able to pay local sellers more competitively than buyers who rely on a single domestic outlet. You are welcome to visit, ask questions and understand exactly how your offer was reached before you decide anything.

The Gold Avenue
Illovo Point, 68 Melville Road, Illovo, Sandton, 2196
Phone: 010 109 0080
WhatsApp: 076 393 5429

Frequently asked questions

Does a diamond hold its value over time?

Diamonds have historically been seen as a store of value, but the market is not a guaranteed straight line upward. Modern prices move with economic cycles, supply from global producers and the growth of lab-grown stones. The realistic resale value of any specific diamond depends on its own quality, type and condition assessed against current market conditions.

Why is my diamond worth less than I paid for it?

Retail prices include margins, branding and setting costs that do not transfer to the resale market. The decades of marketing that taught buyers a diamond is a permanent purchase also discouraged a strong secondhand culture, so many owners overestimate resale value. An honest valuation prices the stone itself, not the original till slip.

How do I know if my diamond is natural or lab-grown?

You usually cannot tell by eye, and even the original paperwork is not always clear. Lab-grown and natural diamonds can look identical but sit in different value brackets. Professional testing is the only reliable way to confirm which you have, which is exactly why we test every stone before making an offer.

Where can I sell a diamond in Sandton?

You can sell diamond jewellery directly to The Gold Avenue at our Illovo premises in Sandton. We assess the piece in front of you, explain the offer and pay the same day by cash or EFT. Contact us first by phone, WhatsApp or online chat to book a valuation.

Learn More

At The Gold Avenue, we simplify the process of selling your valuable assets. From luxury watches and Krugerrands to gold, diamond jewellery, and more, we offer fast, safe, and convenient buying services, coupled with an enjoyable experience. We stand by our promise to provide the best price for your items.

Krugerrands: Sell your Krugerrands swiftly and securely.

Gold Jewellery: Turn your gold jewellery into instant cash.

Gold Coins: Get the best price for your gold coins.

Diamonds: Exchange your diamonds for a competitive price.

Watches: Luxury watches like Rolex and others are welcome.

In need of a cash loan? We’ve got you covered.

Selling to The Gold Avenue is simple:

Contact Our Team: Reach out to our team via call, WhatsApp, or online chat. Describe the luxury items you want to sell.

Book an Appointment: Set a valuation appointment at a time convenient to you. Our safe and secure premises are located in Johannesburg.

Get an Offer: Our expert team will provide a quick and fair valuation. We’re committed to long-term relationships, guaranteeing the best price.

Money in Your Bank: We offer immediate payments, directly into your bank account, either through cash or EFT.

Ready to start selling? Book an Appointment