Turquoise is a captivating gemstone with a history that spans millennia and continents. As one of the primary birthstones for the month of December, it holds a special place in the world of jewelry and gemology. Characterized by its distinctive blue to blue-green hue, turquoise is a mineral that has been prized by ancient civilizations, revered by indigenous cultures, and continues to be a favorite in modern jewelry design. Its opaque nature and unique coloration make it instantly recognizable, often set in sterling silver to create striking and affordable pieces. This article explores the multifaceted nature of turquoise, delving into its geological origins, historical significance, gemological properties, and the practical care required to maintain its beauty.
History and Lore
The history of turquoise is as deep and varied as its color. Evidence of its use dates back over 2000 years in the Southwestern United States, where Native American cultures utilized the stone for beads, pendants, inlay work, and small sculptures. For these cultures, turquoise was not merely an ornamental material; it was an integral part of their spiritual and artistic expression, a tradition that continues to this day in Southwestern art and jewelry.
Beyond the Americas, turquoise has been a gemstone of global importance. Ancient Egyptians mined it as early as 6000 B.C., and it was used in the burial masks of pharaohs, symbolizing protection and rebirth. Persian artisans valued it for its sky-blue color, which they believed was a fragment of the heavens. Across various cultures, turquoise has been associated with protection, good fortune, and healing. According to some sources, turquoise is regarded as a love charm and a symbol of success. It is believed to relax the mind and protect its wearer from harm. Specific beliefs suggest that turquoise rings, in particular, have the power to keep away evil spirits. These enduring metaphysical beliefs have cemented turquoise's status as a stone of significance far beyond its physical beauty.
The journey of turquoise to becoming a modern December birthstone is part of a broader historical trend. The concept of assigning specific gemstones to each month evolved over centuries, with the modern list largely standardized in the early 20th century. Turquoise, with its long history of human use and deep cultural roots, was a natural candidate for inclusion. Its addition provided a durable and meaningful option for those born in the final month of the year, connecting them to a lineage of artisans and believers who have cherished the stone for ages.
Geological Formation and Sources
Turquoise is a hydrous phosphate mineral containing copper and aluminum. Its characteristic blue to blue-green to yellowish-green color is primarily due to the presence of copper, while iron can contribute to greener tones. The formation of turquoise is a geological process that typically occurs in arid regions where acidic, copper-rich water percolates through rocks containing aluminum-bearing minerals. Over time, this process results in the deposition of turquoise in veins and nodules, often within a host rock matrix.
The most significant and historically important sources of turquoise are located in the Southwestern United States. States like Arizona, New Mexico, and Nevada are renowned for their turquoise mines, each producing stones with distinct colors and characteristics. For example, the Sleeping Beauty mine in Arizona is known for its pure, sky-blue turquoise, while the Kingman mine produces a range of blues with a characteristic matrix. The Spiderweb mine in Nevada is famous for its dark blue stone with a distinctive black matrix. These American sources have provided the material for much of the turquoise jewelry used by Native American artisans for centuries.
While the United States is a primary source, turquoise is also mined in other parts of the world. Iran (historically Persia) is famous for its high-quality, smooth turquoise with a robin's egg blue color. China is a major producer of turquoise today, with mines in Hubei province yielding large quantities of material. Other sources include Egypt, Afghanistan, and Chile. The global availability of turquoise contributes to its accessibility and popularity in the jewelry market.
Gemological Properties
Understanding the physical and optical properties of turquoise is essential for gemologists, jewelers, and consumers. As an opaque gemstone, turquoise is typically cut into cabochons—a smooth, rounded shape that showcases its color and any distinctive matrix patterns. The matrix is the host rock material that is often incorporated into the gem, creating unique web-like or spotty patterns that are highly valued by connoisseurs.
Key Gemological Properties of Turquoise:
| Property | Description |
|---|---|
| Color | Blue, blue-green, yellowish-green. Bright blue is most preferred. |
| Transparency | Opaque. |
| Luster | Waxy to subvitreous (vitreous when polished). |
| Crystal System | Triclinic. |
| Hardness | 5 to 6 on the Mohs scale. |
| Durability | Fair to poor. Prone to breakage and abrasion. |
| Cleavage | None. |
| Fracture | Conchoidal to uneven. |
| Specific Gravity | 2.60 to 2.90. |
| Chemical Formula | CuAl₆(PO₄)₄(OH)₈·4H₂O (hydrated copper aluminum phosphate). |
The hardness of turquoise, rated between 5 and 6 on the Mohs scale, is a critical factor in its use. This relatively low hardness means it is susceptible to scratching and abrasion. Consequently, turquoise is classified as having fair to poor durability. It is not recommended for rings or bracelets that are subject to frequent impact and wear unless the stone is set in a protective mounting and the wearer is careful to remove the jewelry during physical activities. Its lack of cleavage is a positive attribute, as it reduces the risk of the stone splitting along a plane, but its overall vulnerability requires mindful handling.
The chemical composition of turquoise is variable, and its stability can be affected by environmental factors. Prolonged exposure to chemicals, cosmetics, and even skin oils can lead to discoloration or a dulling of its luster. This sensitivity underscores the importance of proper care and cleaning.
Care and Cleaning
Given its moderate hardness and sensitivity, turquoise requires specific care to maintain its appearance and structural integrity. The primary rule for cleaning turquoise is to avoid harsh chemicals and ultrasonic cleaners. These can damage the stone's surface, strip its polish, and potentially alter its color.
The recommended method for cleaning turquoise jewelry is simple and gentle. Use a soft, lint-free cloth slightly dampened with lukewarm water. Gently wipe the stone and its setting to remove surface dirt and oils. For more thorough cleaning, a mild, phosphate-free soap can be used, but it must be rinsed completely and dried immediately with a soft cloth. Never soak turquoise jewelry, as prolonged water exposure can weaken the stone and any porous fillers that may have been used to stabilize it.
Storage is also important. Turquoise should be stored separately from other jewelry to prevent scratches from harder gemstones like diamonds or sapphires. A soft pouch or a lined jewelry box compartment is ideal. It is advisable to keep turquoise away from direct sunlight and extreme temperature changes, as these can cause fading or cracking over time.
For jewelry set in sterling silver, additional care is needed. Sterling silver can tarnish when exposed to air and moisture. To clean silver settings, use a specific silver polishing cloth, but take care to avoid rubbing the turquoise stone directly with the polish, as some silver cleaners can be abrasive or contain chemicals harmful to the gem. A jeweler's cloth designed for both silver and gemstones is a safer option.
Symbolism and Metaphysical Beliefs
The symbolism of turquoise is deeply embedded in cultural traditions worldwide. Its color, reminiscent of the sky and water, has led to associations with tranquility, protection, and spiritual grounding. In many Native American cultures, turquoise is considered a sacred stone, representing the sky, water, and the life-giving forces of nature. It is often used in ceremonies and as a conduit for prayer and meditation.
Metaphysical beliefs, as referenced in historical and contemporary sources, attribute several powers to turquoise. It is famously known as a stone of protection, believed to guard against negative energy and physical harm. Some traditions hold that turquoise can signal danger by changing color, although this is a popular belief rather than a scientific property. As a love charm, it is thought to promote fidelity and attract prosperity and success. Its calming energy is said to relieve stress and balance the mind, making it a popular choice for those seeking emotional stability.
While these beliefs fall under the realm of metaphysics and are not validated by gemological science, they are a significant part of turquoise's identity and enduring appeal. For many wearers, the connection to these ancient symbols and intentions adds a layer of personal meaning to their turquoise jewelry, enhancing its value beyond the material.
Conclusion
Turquoise stands as a timeless gemstone, bridging ancient history with modern aesthetics. As a December birthstone, it offers a unique combination of cultural richness, visual beauty, and accessibility. Its journey from the arid mines of the American Southwest and Persia to contemporary jewelry boxes is a testament to its universal appeal. While its physical properties demand careful handling, the reward is a gemstone that carries the legacy of millennia. For those born in December or anyone captivated by its serene hues, turquoise is more than a mineral; it is a piece of the earth's history, a symbol of protection, and a enduring favorite in the world of gems.