Turquoise is an opaque mineral prized for its beautiful blue and green hues. Chemically, it is a hydrous phosphate of copper and aluminum, requiring a specific set of elements and water for its formation. The question of its rarity depends on the definition of the stone, as its presence is not evenly distributed globally. While true, high-quality turquoise is geologically rare, lower-grade material is much more plentiful, leading to confusion about its overall scarcity.
Geographic Concentration and Supply
The formation of turquoise requires a precise and unusual geological environment. It is a secondary mineral that develops when acidic, copper-rich groundwater percolates through aluminous rock formations. This process occurs at relatively low temperatures and favors arid or desert climates where copper deposits are present.
The result is a concentrated global supply, despite turquoise being found on almost every continent. Historically, the most famous sources include the Nishapur region of Iran, which produced the sought-after “Persian Blue” material for over 2,000 years. Ancient deposits were also mined in the Sinai Peninsula of Egypt, dating back to 3000 B.C.
In modern times, the Southwestern United States, particularly Arizona, Nevada, and New Mexico, has become a major source of the world’s supply. China, specifically the Hubei province, is also a significant current producer. This geographic localization means the stone’s supply is finite and subject to the economic and political conditions of a few specific regions.
Geological Factors Driving True Scarcity
The true scarcity of turquoise is defined by the small fraction of mined material that qualifies as natural, gem-quality stone. The vast majority of turquoise is a chalky, porous material too soft to be cut or polished into jewelry without intervention. Only a small percentage, estimated to be as low as five to ten percent, possesses the required natural density and hardness.
Gem-quality turquoise is characterized by its high density and a hardness ranking between 5 and 6 on the Mohs scale. The most desirable color, often described as robin’s egg or sky blue, results from a high copper content within the stone’s chemical structure. Impurities, such as iron, create a less desirable greenish tint.
The structure of the stone is also important. The most valuable pieces have a uniform color and high polish, or feature an attractive, tight spiderweb matrix. Conversely, material with a loose structure is prone to cracking, does not hold a polish, and is susceptible to color change from exposure to oils and sunlight. This distinction between readily available mined rock and the naturally durable gemstone is key to understanding its genuine rarity.
The Impact of Treatment on Market Availability
Despite the geological scarcity of naturally hard, high-grade stone, turquoise appears widely available in the global jewelry market due to treatment processes. Treatments transform the soft, porous, low-quality material into a durable, marketable gem. It is estimated that 90% or more of the turquoise currently sold has been treated or enhanced.
The most common process is stabilization, which involves impregnating the porous, low-grade material with a clear epoxy resin or plastic under pressure. This process dramatically increases the stone’s hardness, allowing it to be cut and polished. Stabilization also locks in the color, preventing it from changing over time, and sometimes the stone is dyed to achieve a more intense blue hue beforehand.
Another common method is reconstitution, where low-grade fragments and turquoise dust are crushed, mixed with a binding resin, and formed into a solid block that can be cut. These enhancement techniques effectively create a massive market supply from otherwise unusable material. While jewelry-ready turquoise is plentiful, natural, untreated stones remain extremely difficult to find and command a significantly higher price. The Zachery treatment is a specialized process that alters the stone’s chemical structure near the surface to improve color and hardness without introducing plastic.
Current State of Reserves and Future Rarity
Turquoise deposits are definitively finite resources, and mining history shows that even the most famous sources are not inexhaustible. Several historically important mines in the Southwestern United States, such as the Sleeping Beauty Mine in Arizona and the Number 8 Mine in Nevada, have closed or been depleted of high-grade material. The closure of these sources has led to a significant increase in the value of their remaining “old stock.”
Many modern turquoise mines operate only as a byproduct of large-scale copper extraction, meaning the focus is not on maximizing the gem yield. This economic reality contributes to the declining supply of new, high-quality rough material entering the market. The natural, untreated, gem-quality stone is becoming increasingly rare as historical reserves are exhausted and new discoveries of comparable quality are infrequent.
While lower-grade material will likely remain available for stabilization, the supply of hard, natural turquoise that requires no treatment is rapidly diminishing. This trend ensures that the finest, untreated stones will continue to see their value and rarity increase over time, solidifying their status as a truly scarce commodity.