Turquoise, the December birthstone, is a gemstone of profound historical depth, geological fascination, and enduring cultural significance. Revered for millennia across continents, its distinctive blue-green hues have captivated civilizations from ancient Egypt to the American Southwest. This article delves into the multifaceted nature of turquoise, exploring its formation, properties, historical journey, and the rich tapestry of beliefs that have surrounded it. As a gemstone that bridges the gap between the earth and the sky, turquoise continues to be a symbol of protection, wisdom, and tranquility for those born in December and for gemstone enthusiasts worldwide.
History and Lore
Turquoise boasts a documented history spanning thousands of years, with its use and veneration recorded in ancient Egypt, China, Persia, and the Americas. In ancient Egypt, turquoise was a potent symbol of life and divine protection. Pharaohs and high-ranking officials adorned themselves with turquoise jewelry and artifacts, believing the stone offered a connection to the heavens and safeguarded the wearer in both life and death. The most famous testament to its importance is the funerary mask of King Tutankhamun, who ruled Egypt more than 3,000 years ago. The mask features intricate turquoise inlays, highlighting its central role in royal and religious contexts.
In China, turquoise was highly prized over 3,000 years ago. Ancient Chinese artisans skillfully carved the stone into intricate forms for both decorative and ceremonial purposes. It was believed to bring good fortune and was often associated with the heavens and the gods, reflecting a spiritual connection that paralleled its significance in other cultures.
The stone’s journey to its modern name is rooted in European trade. The term "turquoise" is derived from the French pierre turquois, meaning "Turkish stone." This name emerged because the gemstone was first brought to Europe from the markets of Turkey, even though its primary sources were in Persia (modern-day Iran). Mineralogists and the jewelry industry have historically used the spelling "turquois" without a final "e," though "turquoise" is the more common form in contemporary usage.
In the New World, turquoise has been integral to the cultures of the Americas for centuries. The Aztecs and Incas utilized the stone, but it is the Native American peoples of the Southwest who have most prominently brought turquoise to global attention in recent times. Their art, particularly squash blossom necklaces and thunderbird motifs, has become iconic. For these cultures, turquoise is sacred, and it was historically used as a shaman’s stone, believed to possess strong metaphysical properties for spiritual growth.
Geological Formation and Sources
Turquoise is a secondary mineral formed through a specific geological process. It develops when water, rich in copper and aluminum, seeps through iron-rich limonite or sandstone. Over millions of years, under the right conditions of temperature and pressure, these minerals coalesce to form turquoise. The presence of copper imparts the stone’s characteristic blue color, while aluminum contributes to its greenish hues. This formation process is why turquoise is often found in nodules or vein-like structures within its host rock.
The matrix—the host rock material that remains within the turquoise—is a key feature, especially in stones from the United States. These vein-like markings are typically tan (from sandstone) or dark brown (from limonite). The presence and prominence of the matrix can influence the stone's value and aesthetic appeal.
Geographically, turquoise has been mined in various locations worldwide for centuries. The Nishapur district of Iran has been a source for over 1,000 years, producing the prized "robin’s egg blue," "sky blue," or "Persian blue" turquoise. This even-colored, intense blue variety is so iconic that trade professionals now use these terms to describe any turquoise of that specific color, regardless of its actual source.
In the United States, turquoise mining has a rich history. While New Mexico was the largest producer until the 1920s, today most U.S. production comes from Arizona and Nevada. Mines with evocative names such as Dry Creek, Easter Blue, Emerald Valley, and Fox contribute to the market. The Kingman mine in Arizona is a historically important source known for its intense blue turquoise. Arizona’s Sleeping Beauty mine, now closed to turquoise mining, was a prolific producer for more than four decades and is renowned for its clean, sky-blue stones without a prominent matrix.
Today, China is the world’s largest producer of turquoise. The Hubei Province in central China is the primary source for most of the gem-quality turquoise currently being mined. This shift in production has made Chinese turquoise a significant presence in the global market.
Gemological Properties
Turquoise is a hydrous phosphate of aluminum and copper, with the chemical formula CuO·3Al₂O₃·2P₂O₅·9H₂O. Its color spectrum ranges from blue to green, influenced by its copper and iron content. The finest and rarest color is an intense, uniform blue, as seen in stones from the Sleeping Beauty mines in Arizona.
On the Mohs scale of hardness, turquoise is a relatively soft stone, rating between 5 and 6. This moderate hardness makes it susceptible to scratching and abrasion, necessitating careful handling and storage. It should be stored separately from harder gemstones like diamonds, sapphires, or rubies to prevent damage.
Due to its porosity and relative softness, some turquoise is treated to enhance its durability, appearance, and polish. Common treatments include dyeing to improve color uniformity and the addition of an epoxy or acrylic resin (stabilization) to increase hardness and improve polish. These treatments are standard in the industry and help make the stone more suitable for jewelry.
The following table summarizes key gemological properties of turquoise based on the provided information:
| Property | Description |
|---|---|
| Chemical Formula | CuO·3Al₂O₃·2P₂O₅·9H₂O (Hydrous phosphate of aluminum and copper) |
| Color | Blue to green, determined by copper (blue) and aluminum (greenish hue) content. |
| Hardness (Mohs Scale) | 5 to 6 |
| Key Features | Often contains a matrix (vein-like markings from host rock). |
| Common Treatments | Dyeing, stabilization with epoxy or acrylic resin. |
Symbolism and Metaphysical Beliefs
Across cultures and eras, turquoise has been imbued with a wide array of symbolic meanings and metaphysical beliefs, often centered on protection, health, and spiritual insight.
In ancient Persia, the stone was believed to ward off unnatural death and was used as a protective talisman. Seeing a turquoise after beholding the new moon was thought to ensure fantastic wealth, according to Hindu mystics.
For Native American cultures, turquoise holds deep spiritual significance. The Apache believed the stone could be found by following a rainbow to its end. They also attached turquoise to bows and firearms, believing it improved the wearer's aim. The Pueblo believed the gem’s color came from the sky, while the Hopi attributed its creation to lizards scurrying over the earth.
In Tibetan and Nepalese cultures, turquoise is revered as the "Sky Stone," believed to have come from the heavens. It is considered a national treasure in Tibet, where it is thought to grant health, good fortune, and protection from evil. Children are often gifted turquoise to keep them safe throughout life. In medieval Europe, turquoise was believed to help achieve a higher state of consciousness and change color to warn of danger or illness, such as poisoning or liver problems (though this latter belief is more of a historical anecdote than a gemological fact).
The stone is also associated with specific life events. In European tradition, the gift of a turquoise ring symbolizes "forget me not." It is the gemstone for the 11th wedding anniversary. Modern interpretations suggest turquoise imparts peace to the wearer and reminds one to witness the expansive beauty of the sky and recollect that same aspect within oneself. It is also associated with the wisdom of compassion and forgiveness.
Care and Cleaning
Given its moderate hardness and porosity, turquoise requires specific care to maintain its beauty and integrity. As a relatively soft stone (Mohs 5-6), it is vulnerable to scratches, acids, heat, and prolonged exposure to sunlight, which can cause fading or discoloration.
To clean turquoise, use only mild soap, lukewarm water, and a soft brush. Avoid ultrasonic cleaners, steam cleaners, and harsh chemicals, including household cleaners, perfumes, and cosmetics, which can damage the stone or its stabilization treatment. After cleaning, rinse thoroughly and dry with a soft, lint-free cloth.
Storage is equally important. Turquoise should be stored separately from other jewelry, preferably in a soft pouch or lined box, to prevent contact with harder materials that could scratch its surface. For jewelry with turquoise set in metal, avoid exposing it to extreme temperature changes, which can cause the metal to expand or contract and potentially loosen the stone.
For treated or stabilized turquoise, these care instructions are even more critical, as the resin or dye can be sensitive to solvents and heat. Always consult a professional jeweler for specific care advice, especially for valuable or heirloom pieces.
Conclusion
Turquoise is more than just a December birthstone; it is a geological marvel and a cultural touchstone. From the tombs of Egyptian pharaohs to the jewelry of Tibetan nomads and the art of Native American silversmiths, its journey through human history is as rich and varied as its color spectrum. Its formation—a slow alchemy of water and minerals—results in a gem that embodies the sky and sea. While its relative softness demands careful handling, its enduring appeal lies in its unique beauty and the profound symbolism it carries. For those born in December, turquoise offers a connection to a legacy of protection, wisdom, and tranquility that spans millennia and continents, making it a truly timeless gemstone.