Those born in the final month of the year are bestowed with a unique distinction among all twelve months: not one, not two, but three official birthstones of dazzling variety. While many months claim a single gem, December offers a triumvirate of choice, each stone representing a different facet of winter’s splendor and a distinct chapter in the history of gemology. The traditional December birthstones—Turquoise, Zircon, and Tanzanite—provide a spectrum of color from sky-blue to vibrant violet-blue, offering a gem for every preference. Together, they symbolize success, wisdom, and transformative growth, weaving a rich narrative of geological wonder, cultural lore, and modern luxury.
The official designation of these three gems is a relatively modern development, yet their individual histories stretch back millennia and into the very recent past. Turquoise is one of the world’s oldest known gemstones, admired for millennia for its protective powers. Zircon, often mistaken for diamond due to its exceptional brilliance, is recognized as the oldest mineral on Earth. Tanzanite, a newcomer to the gemological world discovered in the 20th century, has captivated collectors with its rarity and mesmerizing pleochroism. This article will explore the rich tapestry of history, geology, and symbolism that defines each of December’s extraordinary birthstones, providing a comprehensive guide for enthusiasts, buyers, and students of gemology.
A Legacy of Sky and Earth: Turquoise
Turquoise stands as the ancient cornerstone of December’s birthstone collection, a gem whose name and essence are tied directly to the heavens and the earth. Its name itself tells a story of ancient trade routes, derived from the French phrase pierre turquoise, meaning "stone of Turkey." This nomenclature arose because the gem was introduced to Europe through Turkish bazaars, having traveled from its original sources in the East.
History and Lore The history of turquoise is as old as civilization itself. Its use dates back thousands of years, holding profound cultural significance for numerous indigenous groups in North America. Beyond the Americas, ancient civilizations such as the Egyptians, Persians, and Aztecs revered the stone, incorporating it into their jewelry, art, and funerary objects. The universal appeal of its color—a vibrant blue-green reminiscent of the sky and the sea—made it a powerful symbol across cultures. Traditionally, turquoise has been associated with protection, strength, and success or triumph. It was believed to be a sacred stone that could safeguard the wearer from harm and bring good fortune.
Geological Formation and Sources Turquoise is not formed under the extreme heat and pressure that creates many other gems. Instead, it is a secondary mineral that forms in the Earth’s arid regions where acidic, copper-rich groundwater seeps into the bedrock. Over vast periods, this copper-laden water reacts with minerals containing aluminum and phosphorus. This process creates nodules and veins of opaque turquoise, which is technically a hydrous phosphate of copper and aluminum. The presence of other minerals in the host rock determines the stone's specific shade, ranging from the most prized sky blue to various shades of green. These inclusions often form distinctive, darker patterns known as matrix, which can be seen on the surface of polished stones and are sometimes intentionally highlighted by lapidaries.
Gemological Properties and Care Turquoise is prized for its unique color and opacity. It typically has a Mohs hardness ranging from 5 to 6, making it a relatively soft gemstone compared to others. This moderate hardness, combined with a tendency to be porous, means it requires careful handling. It is susceptible to damage from chemicals, heat, and even prolonged exposure to skin oils and lotions, which can cause discoloration over time. Cleaning should be done gently with a soft, dry cloth. Avoid ultrasonic cleaners and steam cleaning, as these can fracture the stone or strip its surface treatments. Many commercial turquoise stones are stabilized or treated with wax to enhance their color and durability, a common practice in the industry.
The Ancient Fire of Zircon
While turquoise is ancient in its human use, zircon holds the distinction of being the oldest mineral on the planet, a testament to its incredible resilience. This sparkling gem, often confused with the synthetic cubic zirconia, possesses a fire and brilliance that rivals that of a diamond, making it a hidden treasure in the gem world.
History and Lore Zircon’s history is deeply rooted in the Earth’s primordial past. Its chemical composition allows it to withstand immense geological erosion and pressure shifts, surviving from formations billions of years old. In medieval Europe, zircon was believed to be a powerful protective stone. It was worn to ward off evil spirits and was thought to ensure restful sleep by driving away nightmares. Its name is believed to be derived from the Persian word zargun, meaning "gold-colored," though today the gem is most celebrated for its colorless and blue varieties. In modern metaphysical beliefs, zircon is associated with wisdom, balance, and prosperity. It is said to aid in spiritual enlightenment and the development of psychic intuition, making it a fitting stone for the introspective nature often associated with the winter months.
Geological Formation and Sources Zircon is a zirconium silicate (ZrSiO₄) and forms as a primary mineral in igneous and metamorphic rocks. It is found in many parts of the world, including Australia, which is a leading source, as well as Cambodia, Sri Lanka, Thailand, and parts of Africa. The gem’s exceptional hardness, rating 7.5 on the Mohs scale, makes it durable and suitable for all types of jewelry, though its brittleness requires care during cutting and setting to avoid fracture.
Gemological Properties and Care Zircon is renowned for its high refractive index and strong dispersion, which are the optical properties responsible for its exceptional brilliance and "fire." These characteristics make it one of the most dazzling of all natural gemstones. Zircon occurs in a variety of colors, but the colorless variety is often heat-treated to produce brilliant blue stones, which are the most popular for jewelry. This heat treatment is generally stable, but the stone should not be subjected to extreme temperature changes, as it can become brittle. Zircon should be cleaned with warm, soapy water and a soft brush. It is wise to avoid ultrasonic cleaners, especially for stones that have been fracture-filled, and to be gentle to prevent chipping at the girdle.
The Modern Marvel: Tanzanite
Tanzanite is the youngest of the three, a 20th-century discovery that took the gemological world by storm. Its rapid ascent to prominence as a December birthstone is a testament to its singular beauty and rarity.
History and Lore Tanzanite’s story is remarkably recent. It was discovered in the Merelani Hills of northern Tanzania in 1967. The stone quickly gained international fame, and in 2002, the American Gem Trade Association (AGTA) named it an official birthstone for December, recognizing its growing popularity and significance. Its association is with transformation and personal growth. It is often described as a stone of transmutation, helping individuals to move forward and embrace new beginnings, a powerful symbol for the end of one year and the approach of another.
Geological Formation and Sources Tanzanite’s origin story is as unique as the gem itself. It is a variety of the mineral zoisite and is formed under very specific geological conditions that are believed to have occurred only in a single location on Earth: a small, four-square-kilometer mining area in the Merelani Hills of Tanzania. This extreme rarity contributes significantly to its value and allure. The stone’s signature violet-blue color is the result of heat treatment, which is applied to the naturally brownish zoisite crystals after they are mined. This heat treatment is permanent and is a standard industry practice, transforming the raw material into the captivating gem recognized worldwide.
Gemological Properties and Care Tanzanite is celebrated for its deep blue to violet-blue hues and, most notably, its strong trichroism. This property means the stone displays three different colors—typically blue, violet, and a reddish or burgundy hue—when viewed from different crystallographic directions. This dynamic visual characteristic gives the gem a captivating depth and complexity. With a Mohs hardness of 6.5 to 7, it is more durable than turquoise but slightly less so than zircon. Like many gems, it is best cleaned with warm, soapy water and a soft brush. It is susceptible to sharp blows, so protective settings are recommended for rings. To preserve its beauty, it should be kept away from rapid temperature changes and harsh chemicals.
A Spectrum of Blue
A unifying thread among all three of December’s official birthstones is their captivating connection to the color blue. Each gem, however, presents a unique expression of this versatile hue, offering December-born individuals a personalized palette.
- Turquoise offers a distinct blue-green, an opaque and calming color that evokes images of tropical lagoons and desert skies. Its tone is often earthy and organic, shaped by the matrix of the host rock.
- Zircon, particularly in its heat-treated blue form, presents a brilliant, electric blue. Its transparency and diamond-like luster give its color a crisp, vibrant quality that catches the light with dazzling intensity.
- Tanzanite provides the most complex color story, with its signature violet-blue that shifts and changes with the angle of view. It can appear as a rich royal blue, a deep violet, or even a reddish-purple, offering a dynamic and luxurious color experience.
This variety ensures that there is a December stone to suit any style, from the lover of antique artifacts to the connoisseur of modern, high-fashion gems.
Practical Guide to Ownership: Care and Maintenance
Understanding the physical properties of these gems is essential for their long-term care and enjoyment. While all three are suitable for jewelry, their individual characteristics dictate specific maintenance protocols.
Turquoise Care: * Hardness: 5-6 (Relatively soft) * Key Concerns: Porosity, sensitivity to chemicals and heat. * Best Practices: Wipe with a soft, dry cloth after wear. Avoid contact with perfumes, lotions, and household cleaners. Store separately to prevent scratching. Do not use ultrasonic or steam cleaners.
Zircon Care: * Hardness: 7.5 (Durable but brittle) * Key Concerns: Brittleness and potential for chipping. * Best Practices: Clean with warm, soapy water and a soft brush. Avoid ultrasonic cleaners, especially for treated stones. Protect from hard blows and avoid extreme temperature changes.
Tanzanite Care: * Hardness: 6.5-7 (Moderately durable) * Key Concerns: Vulnerability to sharp blows and rapid temperature changes. * Best Practices: Clean with warm, soapy water and a soft brush. Use protective settings for rings worn daily. Avoid ultrasonic cleaners and sudden temperature shifts.
Conclusion
The birthstones of December—Turquoise, Zircon, and Tanzanite—offer a remarkable journey through geological time and human history. From the ancient, protective power of turquoise, worn by civilizations for thousands of years, to the primordial resilience of zircon, the oldest mineral known to science, and the breathtaking rarity of tanzanite, a modern marvel from a single source in Tanzania, these gems provide a rich and diverse selection. Their shared spectrum of blue, from the opaque and earthy to the brilliant and electric, unites them in a theme of celestial beauty. For those born in December, the choice is not merely aesthetic but an opportunity to connect with a legacy of wisdom, transformation, and triumph that is as deep and enduring as the gems themselves.