The perception of gold and diamonds as ultimate symbols of wealth suggests both are scarce, but the question of which is truly rarer requires a layered comparison. Answering this involves defining rarity in two distinct ways: first, by looking at their natural occurrence within the Earth’s crust, and second, by examining their availability in the global marketplace. The geological reality of their formation differs significantly from the economic realities of their supply chains. A scientific analysis of crustal concentration provides one answer, while an understanding of human-controlled supply dynamics offers a completely different perspective on scarcity. This comparison reveals that the term “rare” applies to each material in a unique context.
Geological Abundance
The natural scarcity of gold is rooted in its extremely low concentration across the Earth’s outer layer. Gold is a siderophile element, meaning it is iron-loving, and during the planet’s formation, most of the gold sank to the Earth’s core. What remains in the crust is present in trace amounts, with the average concentration estimated to be just 1 to 4 parts per billion (ppb).
The gold that humans mine is found in deposits where geological processes have concentrated it by factors of thousands, often through hydrothermal fluid circulation or magmatic processes. Diamond formation, however, requires a completely different set of circumstances. Diamonds are crystals of pure carbon formed deep within the Earth’s mantle, approximately 150 to 450 kilometers below the surface, under immense pressure and temperatures exceeding 1,000 degrees Celsius.
They are brought to the surface in a rare, explosive volcanic event involving a rock called kimberlite, which moves the diamonds rapidly up through carrot-shaped vertical structures known as kimberlite pipes. Only a small fraction of these kimberlite pipes contain enough diamonds to be economically viable, and they are typically found only in the oldest, most stable sections of the continents called cratons. The conditions for diamond creation are geographically localized and dependent on ancient geological processes, whereas gold is chemically less abundant across the crust overall, but more widely distributed.
Supply Dynamics and Market Availability
The market scarcity of diamonds is less a reflection of their geological rarity and more a result of decades of strategic supply management. For much of the 20th century, a single entity, De Beers, controlled the vast majority of the world’s rough diamond supply. This control was maintained by centralizing distribution and stockpiling diamonds, which limited the flow of stones to the market and effectively manufactured an artificial scarcity, keeping prices high.
Even with the historical monopoly significantly weakened, new natural diamond supply remains constrained by a scarcity of large new discoveries and lengthy mine development timelines. This limited new supply, coupled with continuous marketing efforts that reinforce the diamond’s desirability, maintains its elevated market value as a luxury consumer good. The supply of gold, by contrast, is far more transparent and decentralized, functioning as a global financial commodity.
Central banks and government institutions collectively hold a significant portion of all the gold ever mined, accounting for nearly 20% of the above-ground stock. An existing supply is already circulating in the form of jewelry, coins, and investment bars. This above-ground inventory, combined with the estimated 64,000 tonnes of economically recoverable reserves still underground, means gold’s availability is driven by investor demand and global economic stability, not by a single entity controlling the rough supply.
The Definitive Answer: Gold vs. Diamonds
When the comparison is based purely on natural occurrence, gold is the rarer substance in the Earth’s crust. Its average concentration of a few parts per billion makes it chemically less abundant than the carbon required for diamond formation.
Diamonds, however, are rarer in terms of their delivery to the surface in concentrated, mineable deposits, which only occurs through the extremely specific and infrequent eruption of kimberlite pipes. Furthermore, the market availability of investment-grade diamonds is significantly more restricted than that of gold. Gold has a vast, measurable above-ground stock that is actively traded as a commodity and financial hedge.
The supply of gem-quality diamonds remains tightly controlled by a few major players, leading to a rarity that is more economic and structural than purely geological. Therefore, gold is fundamentally rarer as an element in the Earth’s crust, but diamonds are rarer in the controlled, accessible market of luxury goods.