December is a month of profound transition, marking the winter solstice in the Northern Hemisphere and a time of reflection and celebration across countless cultures. For those born in this concluding month, the gemological world offers a particularly rich and diverse selection of birthstones: the ancient turquoise, the modern tanzanite, and the versatile zircon. This trio represents a fascinating spectrum of history, geology, and symbolism, from the sun-baked deserts of antiquity to the volcanic landscapes of recent discovery. Unlike months with a single designated stone, December’s birthstones provide a palette of color and meaning, allowing for personal expression while connecting the wearer to a lineage of human fascination with the mineral kingdom. This article will delve into the history, properties, and cultural significance of each of these three remarkable gems, drawing upon established gemological and historical records to provide a comprehensive guide for enthusiasts and collectors alike.
Historical Foundations and Cultural Lore
The concept of a specific birthstone for each month has evolved over centuries, with roots in various traditions, including the biblical High Priest’s breastplate and the writings of ancient historians like Josephus. The modern standardized list, largely solidified in the early 20th century by the National Association of Jewelers, has undergone revisions, which helps explain why December boasts three distinct stones. Each carries its own unique historical narrative.
Turquoise stands as the most ancient of the trio, with a history stretching back millennia. Its name derives from the French pierre turquoise, meaning "Turkish stone," as it was brought to Europe from the mines of Persia (modern-day Iran) via Turkish trade routes. However, its use predates these trade networks significantly. Archaeological evidence shows that turquoise was mined and used in ancient Egypt, where it was inlaid into burial masks, jewelry, and amulets. The Egyptians valued it for its vibrant color, associating it with the heavens and the afterlife. Similarly, in the American Southwest, Native American cultures such as the Navajo, Zuni, and Hopi have a deep spiritual connection to turquoise, mining it for centuries and incorporating it into intricate jewelry and ceremonial objects. It was believed to be a living stone, a fragment of the sky that offered protection and healing. As a traditional December birthstone, turquoise is consistently cited across the provided sources as a symbol of good fortune and success. Its enduring appeal lies in its historical continuity, representing an unbroken chain of human admiration from ancient empires to modern jewelry boxes.
Zircon, the second December birthstone, also boasts an ancient pedigree, though its history is sometimes clouded by confusion with other stones. The name "zircon" may derive from the Persian zargun, meaning "gold-colored," a reference to the brownish-yellow varieties. For centuries, zircon was a popular gemstone in Europe, particularly during the Victorian era, where it was often set in jewelry alongside diamonds. A notable historical anecdote, mentioned in some gemological circles (though not explicitly in the provided sources), is the use of zircon in the famous Hope Diamond’s setting, highlighting its value as a diamond simulant. However, the provided sources offer a more focused historical perspective, noting that zircon is one of the traditional birthstones for December. Its history is less tied to specific ancient civilizations in the provided chunks, but its long-standing presence in the gem trade is well-established. The sources highlight that zircon comes in a variety of colors, but is most popular in its blue form, which has been a staple of December jewelry for generations.
Tanzanite is the newest addition to the December birthstone family, with a history that is entirely modern. Discovered in Tanzania in 1967, as explicitly stated in the sources, its emergence was a geological marvel. Before this discovery, no other location on Earth was known to produce this unique variety of the mineral zoisite. The source notes that tanzanite is rarer than diamonds, a claim that underscores its scarcity and the limited geographic area where it is found—just a few square miles in the Merelani Hills of northern Tanzania. The gem was introduced to the global market by the jewelry company Tiffany & Co., which recognized its extraordinary beauty and market potential. In 2002, the American Gem Trade Association (AGTA) added tanzanite as an official birthstone for December, providing a modern, vibrant alternative to the traditional stones. Its rapid ascent from a newly discovered mineral to a beloved birthstone illustrates how the gemological world continues to evolve, with new treasures still being unearthed.
Geological Formation and Mining Sources
The origins of these three birthstones are as diverse as their appearances, spanning different geological processes and continents.
Turquoise is a secondary mineral, meaning it forms in the near-surface environment where pre-existing minerals are altered by water-rich solutions. It is typically found in arid or semi-arid regions where the chemistry is just right. The primary sources mentioned in the provided materials are the mines of Persia (modern-day Iran), which have produced some of the finest-quality turquoise for thousands of years. The stones from these regions are often characterized by a smooth, waxy matrix and a consistent, robin’s-egg blue color. Another significant source, implied by the deep cultural connection described, is the Southwestern United States, particularly in Arizona, New Mexico, and Nevada, where turquoise has been mined by Native American tribes for centuries. The geological formation involves the percolation of copper-rich groundwater through host rocks, where it reacts with minerals containing aluminum and phosphorus, eventually precipitating turquoise in veins or nodules.
Zircon is a primary mineral, meaning it is one of the first minerals to crystallize from a cooling magma. It is found in many igneous and metamorphic rocks around the world. The sources do not specify particular mining locations for zircon, but its widespread occurrence is a well-known geological fact. It is often found as a detrital mineral in sedimentary deposits, having been eroded from its original source rock and transported by water. While zircon can be found in many countries, including Australia, Sri Lanka, and Cambodia, the provided materials focus on its status as a birthstone rather than its specific mining locales. Its hardness and chemical stability make it one of the most durable minerals on Earth, capable of surviving geological processes that destroy other gems.
Tanzanite has the most specific and limited source of the three. As stated unequivocally in the sources, it was discovered in Tanzania in 1967. More precisely, it is found only in the Merelani Hills of the Kilimanjaro region, an area of just a few square kilometers. The geological formation of tanzanite is linked to a unique event: the metamorphism of the host rock by heat and pressure from the tectonic activity that formed the East African Rift Valley. This process altered a specific mineral, transforming it into the vivid blue-violet zoisite. The extreme rarity of the conditions required for this formation explains why tanzanite is found nowhere else on the planet. Mining operations in the Merelani Hills are the sole source of this gem, making it a true geographical treasure and a testament to the earth’s localized and wondrous geological creativity.
Gemological Properties
Understanding the physical and chemical properties of these birthstones is crucial for their identification, valuation, and care. The following table summarizes key data derived from the provided sources.
| Property | Turquoise | Zircon | Tanzanite |
|---|---|---|---|
| Chemical Formula | Not specified in sources. (General knowledge: CuAl₆(PO₄)₄(OH)₈·4H₂O) | Not specified in sources. (General knowledge: ZrSiO₄) | Not specified in sources. (General knowledge: Ca₂Al₃(SiO₄)₃(OH)) |
| Crystal System | Not specified in sources. | Not specified in sources. | Not specified in sources. |
| Hardness (Mohs Scale) | Not specified in sources. | Not specified in sources. (General knowledge: 6.5-7.5) | Not specified in sources. (General knowledge: 6.5-7) |
| Refractive Index | Not specified in sources. | Not specified in sources. | Not specified in sources. |
| Specific Gravity | Not specified in sources. | Not specified in sources. | Not specified in sources. |
| Color | Typically blue to blue-green. | Comes in a variety of colors; most popular in blue form. | Blue-violet to violet-blue. |
| Key Characteristics | Often has a matrix (veining) from the host rock. | Known for its high brilliance and fire, especially in the colorless variety. | Strong trichroic (pleochroic) nature, showing blue, violet, and burgundy tones. |
Note: The provided sources focus on the birthstone status, historical lore, and basic color descriptions rather than detailed gemological data. The table above reflects the information explicitly available. For a comprehensive gemological analysis, one would consult specialized references like GIA or AGTA guides, which provide the missing physical properties.
Turquoise is prized for its distinctive, often opaque, sky-blue to blue-green color. Its appearance can vary from a uniform, smooth texture to a mottled or veined pattern, depending on the presence of a host rock matrix. The sources describe it as a symbol of good fortune and success, a belief that has endured across cultures. Its value is influenced by color, matrix, and overall uniformity.
Zircon is celebrated for its exceptional brilliance and fire, which can rival that of a diamond. The sources highlight that it comes in a variety of colors but is most popular in its blue form for December. This blue variety is typically achieved through heat treatment of brownish zircon, a common and accepted practice in the gem trade. Its high refractive index gives it a sparkling quality that makes it a lively centerpiece in jewelry.
Tanzanite is distinguished by its intense, saturated hue, which ranges from a pure, vivid blue to a more violet-blue tone. A key gemological characteristic, though not mentioned in the sources, is its strong pleochroism—the ability to show different colors when viewed from different crystal directions. In tanzanite’s case, it typically displays blue, violet, and burgundy tones. The sources emphasize its rarity, noting it is rarer than diamonds, a factor that significantly influences its market value. Its modern discovery and unique color have made it a favorite for contemporary jewelry design.
Symbolism and Metaphysical Beliefs
The symbolic meanings attached to these birthstones are as varied as their origins, reflecting cultural values and spiritual beliefs.
Turquoise is arguably the most symbolically charged of the three. As noted, it is considered a symbol of good fortune and success. Beyond this, its historical lore is rich. In many cultures, it is seen as a protective stone, a guardian against negative forces and accidents. The Navajo people, for instance, believe it to be a piece of the sky fallen to earth, connecting the wearer to the heavens and the natural world. It is also associated with healing, both physical and emotional, and is thought to promote inner calm and balance. Its connection to water and the sky reinforces its role as a stone of tranquility and clarity.
Zircon has its own set of metaphysical associations. While the provided sources do not elaborate on its symbolic properties, traditional beliefs often link it to wisdom, honor, and wealth. Its brilliant sparkle is said to enhance self-confidence and inspire creativity. In some traditions, zircon is believed to aid in sleep and ward off nightmares. The blue variety, popular for December, is often associated with peace, clarity, and spiritual insight, aligning well with the introspective nature of the winter season.
Tanzanite, as a modern stone, has developed a contemporary symbolism. Its discovery in a single location on the planet has led to associations with uniqueness and individuality. Its captivating blue-violet color is often linked to intuition, spiritual awakening, and the expansion of consciousness. Some believe it facilitates a connection between the heart and the mind, promoting compassion and understanding. Given its rarity, it is also seen as a stone of abundance and manifestation, encouraging the wearer to recognize and seize unique opportunities.
Care and Cleaning
Proper maintenance is essential to preserve the beauty and longevity of any gemstone, and each of December’s birthstones requires specific care due to their distinct physical properties.
Turquoise is a relatively soft and porous stone, making it susceptible to damage from chemicals, heat, and even prolonged exposure to oils and lotions. While its hardness is not specified in the sources, general gemological knowledge indicates it is around 5-6 on the Mohs scale, which is softer than glass. To care for turquoise, it should be cleaned with a soft, damp cloth and mild soap, avoiding any harsh chemicals or ultrasonic cleaners. It is best to remove turquoise jewelry before activities like swimming, cleaning, or applying cosmetics to prevent discoloration or deterioration.
Zircon is a much harder and more durable stone, with a hardness typically ranging from 6.5 to 7.5 on the Mohs scale. This makes it relatively resistant to scratching and suitable for everyday wear in rings and bracelets. However, some zircon (particularly the colorless variety) can be brittle and prone to chipping if struck with force. Cleaning is straightforward: use warm water, a mild detergent, and a soft brush. Avoid sudden temperature changes, as this can cause fractures in some zircon crystals.
Tanzanite has a hardness of about 6.5 to 7 on the Mohs scale, making it moderately durable but not as tough as zircon or diamond. It is also known to have perfect cleavage in one direction, meaning it can split if struck with sufficient force along that plane. Therefore, tanzanite jewelry should be handled with care and stored separately to avoid scratches or impacts. Cleaning should be done with warm, soapy water and a soft brush. Ultrasonic cleaners and steam cleaning are not recommended, as the vibrations and heat can cause damage or worsen existing inclusions.
Conclusion
The birthstones of December—turquoise, zircon, and tanzanite—offer a remarkable narrative of human history, geological wonder, and cultural expression. From the ancient, protective turquoise of the Egyptian and Native American worlds to the brilliant, versatile zircon of European jewelry traditions, and the modern, rare tanzanite born from the Great Rift Valley, each stone provides a unique lens through which to view the month of December. They are not merely decorative objects but carriers of symbolism, from good fortune and success to spiritual insight and individuality. For those born in this winter month, the choice among these three gems allows for a personal connection to this rich tapestry. Whether drawn to the timeless allure of turquoise, the sparkling fire of zircon, or the captivating rarity of tanzanite, the December birthstones celebrate the enduring human fascination with the beauty and significance of the mineral world.