The birthstones for December 27th—Tanzanite, Turquoise, and Zircon—represent a fascinating convergence of ancient tradition and modern discovery. Each gemstone carries a unique legacy, from the millennia-old reverence for Turquoise to the recent, meteoric rise of Tanzanite in the gemological world. For individuals born on this day, these stones offer a palette of colors and meanings, embodying the cool, serene essence of December. This article provides a comprehensive exploration of these gemstones, focusing on their historical significance, geological origins, gemological properties, and the cultural symbolism that has cemented their status as December's treasures.
Tanzanite, in particular, has captured the global imagination since its discovery in the late 20th century. Its vivid blue and violet hues, unlike any other natural gemstone, have made it a modern classic. Turquoise, with its storied past across continents, offers a connection to ancient civilizations and a timeless appeal. Zircon, often mistaken for cubic zirconia, is one of the oldest minerals on Earth, boasting exceptional brilliance and a spectrum of colors. Together, they form a triad of gems that celebrate the individuality of those born on December 27th, each offering distinct aesthetic and metaphysical qualities.
History and Lore
The historical narratives of these three gemstones span vastly different timelines, from ancient antiquity to the modern era. Turquoise holds the distinction of being one of the earliest known gems to be mined and used in jewelry and ornamentation. Its history is deeply interwoven with the cultures of the Middle East, Central Asia, and the Americas. For millennia, it has been prized not only for its distinctive color but also for its perceived protective qualities. Ancient Persian rulers adorned themselves with Turquoise, believing it to ward off the "evil eye" and bring good fortune. In the Americas, Native American tribes, particularly the Navajo, Zuni, and Pueblo peoples, have a profound cultural connection to Turquoise, incorporating it into intricate jewelry and ceremonial objects for centuries. The stone's name is derived from the French "pierre turquoise," meaning "Turkish stone," reflecting its historical trade route through Turkey to Europe.
In stark contrast, Tanzanite is a product of the 20th century. Its discovery is a relatively recent event in the gemological world, dating back to 1967. Tanzanite was found in the Merelani Hills of northern Tanzania, near the foothills of Mount Kilimanjaro. This specific geographic location is currently the only known commercial source of this unique gemstone. The mineral is a variety of zoisite, and its vibrant blue-violet coloration is the result of trace amounts of vanadium within its crystal structure, a color phenomenon that is further enhanced by a controlled heat treatment process. Its rapid ascent to prominence was fueled by a major gemological and marketing partnership, which positioned it as a rare and exclusive gemstone, leading to its inclusion as a modern birthstone for December.
Zircon, on the other hand, boasts a history that is ancient in the truest sense. As one of the oldest minerals on Earth, zircon crystals have been found in sediments that date back billions of years. The name "zircon" may derive from the Persian word "zargun," which translates to "gold-colored," a reference to the gemstone's common brownish hues. However, zircon is celebrated for its brilliant fire and clarity, qualities that made it a popular gemstone in the Victorian era. For centuries, it has been used as a diamond simulant due to its high refractive index and strong dispersion (fire). While its history is long, its status as a birthstone is more recent, having been officially recognized as a December birthstone in the modern list adopted by the American Gem Trade Association (AGTA) in 2002, which also included Tanzanite.
Geological Formation and Sources
The origins of these gemstones are as diverse as their histories, each formed under unique geological conditions and sourced from distinct regions of the world.
Turquoise is a secondary mineral, meaning it is not formed directly from magma but through the alteration of pre-existing rocks. It forms in arid or semi-arid regions where acidic, copper-rich groundwater percolates through rocks containing aluminum and phosphorus. Over millions of years, this process results in the deposition of turquoise in nodules, veins, or as a coating. The most significant sources of turquoise include: * Iran (Persia): Historically the most prized source, producing the famous "robin's egg blue" variety. * United States: Major deposits are found in Arizona (e.g., Sleeping Beauty, Morenci), Nevada (e.g., Lander Blue, Royston), and New Mexico. American turquoise is known for its wide range of colors and often distinctive matrix (the host rock incorporated into the gem). * China: A major modern producer of turquoise, often with a greenish-blue hue and a dark matrix. * Egypt: The ancient mines of Sinai Peninsula were a primary source for the Egyptian civilization.
Tanzanite is a geologically young gemstone, formed from the alteration of metamorphic rocks. Its formation is linked to specific geological events in the East African Rift system. The intense heat and pressure from tectonic activity caused the metamorphism of rocks containing zoisite, with the addition of vanadium from nearby sources creating the gem's signature color. The primary—and currently only significant—commercial source is the Merelani Hills in Tanzania. The gem is found in three main mining blocks (A, B, and C), with Block C being the most productive. Due to its singular source location, Tanzanite is considered to have a limited supply, adding to its rarity and value.
Zircon is a primary mineral, meaning it crystallizes directly from magma. It forms in pegmatites, granites, and metamorphic rocks. Zircon crystals are highly durable and resistant to weathering, which is why they are often found in sedimentary deposits as well. The gemstone's color is influenced by trace elements (such as uranium, thorium, and iron) and heat treatment. Major sources of gem-quality zircon include: * Cambodia: Known for producing high-quality, heat-treated blue zircon. * Sri Lanka: A traditional source for a variety of zircon colors, including brown and green. * Myanmar (Burma): Produces zircon in various colors. * Australia: Known for producing zircon in a range of colors, including green and yellow. * United States: Deposits are found in states like California, Colorado, and Montana.
Gemological Properties
Understanding the physical and chemical properties of these gemstones is crucial for their identification, valuation, and care. The following table summarizes the key gemological characteristics of Tanzanite, Turquoise, and Zircon based on authoritative gemological data.
| Property | Tanzanite | Turquoise | Zircon |
|---|---|---|---|
| Mineral Group | Zoisite (a variety of) | Hydrated phosphate of copper and aluminum | Zirconium silicate |
| Chemical Formula | Ca₂Al₃(SiO₄)₃(OH) | CuAl₆(PO₄)₄(OH)₈·4H₂O | ZrSiO₄ |
| Crystal System | Orthorhombic | Triclinic | Tetragonal |
| Hardness (Mohs) | 6.5 - 7 | 5 - 6 (often 5-5.5 in jewelry-grade) | 7.5 |
| Refractive Index | 1.690 - 1.700 | 1.610 - 1.650 | 1.92 - 2.01 |
| Specific Gravity | 3.35 | 2.60 - 2.90 | 4.60 - 4.70 |
| Luster | Vitreous (glass-like) | Waxy to vitreous | Adamantine (diamond-like) |
| Color | Blue, violet, purple, often with pleochroism (shows different colors from different angles) | Sky blue, blue-green, greenish blue; often with a matrix (web of host rock) | Colorless, blue, yellow, brown, green, red; blue is most valued |
| Transparency | Transparent to translucent | Opaque to translucent | Transparent to translucent |
| Notable Features | Strong pleochroism; heat treatment is standard and accepted. | Porosity and sensitivity to chemicals; often stabilized or treated. | High dispersion (fire); can be brittle due to cleavage. |
Tanzanite is prized for its strong trichroism (showing three different colors: blue, violet, and burgundy-red) and its intense saturation. The vast majority of commercial Tanzanite is heat-treated to remove brownish components and enhance its blue and violet hues, a process that is stable and widely accepted in the gem trade.
Turquoise is valued for its unique sky-blue color, but its porosity makes it susceptible to fading, discoloration, and damage from chemicals, perfumes, and perspiration. To improve durability and color, turquoise is often treated with methods such as stabilization (impregnation with a clear resin or wax) or dyeing. The presence of a matrix (the host rock) can be a natural feature, and its pattern and color significantly affect the stone's appearance and value.
Zircon is one of the few natural gemstones with a refractive index and dispersion (fire) comparable to diamond. Its high refractive index gives it exceptional brilliance, while its strong dispersion produces flashes of spectral color. However, zircon has perfect cleavage in two directions, making it relatively brittle and prone to chipping if struck hard. Most brown zircon is heat-treated to produce a more desirable blue color; this treatment is permanent and stable.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, these gemstones are imbued with a rich tapestry of symbolic meanings and metaphysical beliefs, which have evolved over centuries and continue to resonate with modern wearers.
Turquoise is universally regarded as a stone of protection, healing, and good fortune. Across many cultures, it is believed to ward off negative energy and bring peace and serenity to the wearer. In Persian tradition, it was considered a symbol of purity and a conduit for divine protection. Native American cultures view Turquoise as a sacred stone, representing the sky and water, and a gift from the gods that offers healing and spiritual grounding. Metaphysically, it is associated with the throat chakra, promoting honest communication and self-expression. It is also believed to have calming effects, helping to alleviate stress and anxiety.
Tanzanite, as a modern gemstone, has quickly developed its own set of symbolic associations. It is often linked to clarity, calmness, and spiritual insight. Its captivating color is thought to stimulate the third eye and crown chakras, enhancing intuition, meditation, and higher consciousness. For those born on December 27th, Tanzanite is said to promote self-awareness and enlightenment, serving as a companion for personal growth and emotional healing. Its soothing energy is believed to alleviate stress and foster a sense of tranquility, aligning with the introspective and creative nature often associated with Capricorn, the zodiac sign for late December.
Zircon, particularly blue zircon, is associated with wisdom, prosperity, and protection. Historically, it was believed to promote honor and purity in its wearer. Blue zircon, with its icy, serene hue, is thought to bring peace and rest, making it a popular stone for meditation and spiritual work. It is also associated with the root chakra, providing a sense of stability and grounding. In some beliefs, zircon is said to aid in the pursuit of knowledge and to enhance spiritual growth. Its brilliant fire is seen as a symbol of inner light and clarity of thought.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these gemstones, with each requiring specific attention due to their distinct physical properties.
Turquoise demands the most careful handling. Its porous nature makes it vulnerable to damage. To clean turquoise jewelry, use only lukewarm water, a mild soap, and a soft brush. Avoid any chemicals, including household cleaners, perfumes, and hairsprays, which can cause discoloration or erosion of the stone's surface. Ultrasonic and steam cleaners are strictly prohibited, as they can crack or damage the stone. It is advisable to store turquoise separately from other jewelry to prevent scratching and to keep it away from direct sunlight and heat, which can cause fading.
Tanzanite, with a Mohs hardness of 6.5 to 7, is relatively durable but still requires care. It can be cleaned with warm water, mild dish soap, and a soft brush. Ultrasonic cleaners should be avoided, as the vibrations can potentially cause damage, especially if the stone has internal inclusions. Steam cleaning is also not recommended due to the risk of thermal shock. When setting Tanzanite in jewelry, it is best to choose protective settings like bezels or halo settings to guard against impact, given its relative softness compared to harder gems like sapphire or diamond.
Zircon, despite its high hardness of 7.5, is brittle due to its perfect cleavage. It should be protected from hard blows and sharp impacts. Cleaning can be done with warm soapy water and a soft brush, but avoid ultrasonic cleaners and steam, as the vibrations and rapid temperature changes can cause fractures. It is also advisable to avoid sudden temperature changes. Given its brittleness, zircon is often set in jewelry with protective settings to minimize the risk of chipping.
Conclusion
The birthstones for December 27th—Tanzanite, Turquoise, and Zircon—offer a remarkable journey through time, geology, and symbolism. From the ancient, protective allure of Turquoise to the modern, visionary appeal of Tanzanite and the ancient, brilliant fire of Zircon, each gemstone provides a unique lens through which to appreciate the artistry of nature. Their diverse origins, from the arid deserts of Iran and the American Southwest to the volcanic rifts of East Asia and the ancient crust of the Earth, underscore the planet's incredible capacity to produce beauty. For those born on December 27th, these stones are more than mere adornments; they are personal talismans, connecting the wearer to a legacy of cultural significance and natural wonder. Whether chosen for their aesthetic beauty, historical depth, or metaphysical properties, Tanzanite, Turquoise, and Zircon remain enduring symbols of December's serene and captivating spirit.