The month of December is uniquely distinguished in the world of gemstones, offering not one, but three official birthstones that capture the essence of the winter season. While many months claim a single gem, December’s identity is defined by a trio of blue stones: the traditional Turquoise, the modern Tanzanite, and the brilliant Zircon. Each possesses a distinct geological origin, a unique history, and a specific set of properties that appeal to collectors, jewelers, and those born in the final month of the year. The color blue serves as the unifying theme, reflecting the clear, cold skies and deep waters associated with this time of year. This comprehensive guide explores the rich tapestry of history, science, and symbolism woven into these three remarkable gems.
The journey to establishing this triad of birthstones was a gradual process, shaped by tradition and modern industry standards. The traditional birthstone for December has long been the sky-blue to greenish-blue Turquoise. However, as the 20th century progressed, the need for more variety and commercially viable options led to the addition of other blue gems. In 1952, the Jewelry Industry Council of America updated the official list, adding Blue Zircon to December’s offerings. Later, in 2002, the American Gem Trade Association (AGTA) added the recently discovered Tanzanite, recognizing its rising popularity and stunning beauty. Today, these three stones, along with the often-cited alternative Blue Topaz, provide a spectrum of blue choices for December-born individuals.
History and Lore
The history of these gems stretches back millennia, with Turquoise holding the most ancient claim to fame. The very name "Turquoise" is derived from the French phrase pierre turquoise, meaning "stone of Turkey." This nomenclature arose because the stone was initially brought to Europe from Turkish bazaars, though its sources have always been much farther east. Turquoise has been a symbol of protection, power, and good fortune for numerous cultures. It was a prized gem in ancient Egypt, where it was used to create intricate inlays and amulets. The stone’s association with success, happiness, and prosperity has made it a perennial favorite for talismans and jewelry throughout history.
In stark contrast to the ancient lineage of Turquoise, Tanzanite is a very recent addition to the gemological world. Discovered in the mid-20th century in a single, small area of Northern Tanzania, this gem’s history is one of modern discovery and rapid ascent to prominence. Its alluring violet-blue hue, which can shift depending on the light, immediately captured the attention of the global jewelry market. The name "Tanzanite" itself was trademarked by the Tiffany & Co. jewelry company, which introduced the stone to the world in 1968 and promoted it heavily, cementing its status as a significant modern gemstone.
Zircon, the third official December birthstone, has a history that is both long and often misunderstood due to its frequent confusion with the synthetic material, cubic zirconia. Natural Zircon is one of the oldest minerals on Earth, with some specimens dating back billions of years. Historically, colorless Zircon was a popular diamond simulant, valued for its high refractive index and brilliant fire. The blue variety, which is the most sought-after for December birthstones, is typically achieved through heat treatment of brownish zircon. This process enhances its desirable blue color, making it a sparkling and affordable alternative to other blue gems.
Geological Formation and Sources
Understanding the origins of these stones reveals the incredible diversity of geological processes that create gemstones. Turquoise is an opaque mineral that forms near the surface of the earth in arid regions. It is a hydrous phosphate of copper and aluminum, and its characteristic blue and green colors are directly influenced by the amount of copper present during its formation. Groundwater containing copper seeps into the bedrock, and over vast periods, reactions with other minerals create the solid, opaque stone. The dark lines and web-like patterns often seen in Turquoise are known as "matrix," which is the remnants of the surrounding host rock incorporated into the gem.
Tanzanite is a variety of the mineral zoisite and is found in only one known location in the world: the Merelani Hills of Northern Tanzania. Its formation is a geological anomaly, believed to have occurred millions of years ago when a massive tectonic plate shift subjected the zoisite crystals to intense heat and pressure, transforming them into the vibrant blue gems we see today. This extremely limited geographic source makes Tanzanite one of the rarest gemstones, a fact that contributes significantly to its value and allure.
Zircon is a mineral belonging to the nesosilicates group and is found in a variety of geological environments. It is a common constituent of many igneous and metamorphic rocks and is known for its remarkable durability and resistance to chemical and physical wear. Major sources for gem-quality Zircon include Sri Lanka, Brazil, Nigeria, and other locations around the world. Unlike Tanzanite, Zircon is not restricted to a single source, making it more widely available, though high-quality blue Zircon remains a prized find.
Gemological Properties
The three December birthstones differ significantly in their physical and chemical properties, which in turn dictates their suitability for different types of jewelry and their care requirements.
Turquoise is prized for its color and opacity, not its brilliance. It is relatively soft compared to other gemstones, ranking between 5 and 6 on the Mohs hardness scale. This softness makes it susceptible to scratches and damage from chemicals, soaps, and lotions. Its chemical composition is a hydrated phosphate of copper and aluminum. Because it is porous, Turquoise is often stabilized (treated with wax or resin) to enhance its durability and color. It does not possess the refractive index or brilliance of transparent gems; its beauty lies in its unique, waxy luster and characteristic matrix patterns.
Tanzanite is a much harder and more brilliant stone. It ranks between 6.5 and 7 on the Mohs scale, making it more durable than Turquoise but still requiring careful handling. Its most remarkable property is its strong trichroism, meaning it can display three different colors when viewed from different crystallographic directions: blue, violet, and reddish-brown. Most of the commercially available Tanzanite is heat-treated to remove the brownish tones and produce the desirable blue-violet color. Its refractive index is moderate, and it has perfect cleavage in one direction, which makes it vulnerable to breakage if struck with force.
Zircon is the hardest and most brilliant of the trio, ranking 7.5 on the Mohs scale, which makes it an excellent choice for rings and jewelry intended for daily wear. It possesses a very high refractive index, even higher than that of a diamond, giving it exceptional brilliance and fire. Blue Zircon, in particular, is known for its dazzling sparkle. Like Tanzanite, most blue Zircon is heat-treated to achieve its color from original brownish stones. It is important to note that Zircon is a natural gemstone, entirely distinct from the synthetic material known as cubic zirconia (CZ).
Comparative Properties of December Birthstones
| Property | Turquoise | Tanzanite | Blue Zircon |
|---|---|---|---|
| Mineral Family | Phosphate | Zoisite (Nesosilicate) | Zircon (Nesosilicate) |
| Chemical Formula | Hydrated Cu & Al Phosphate | Ca2Al3(SiO4)3(OH) | ZrSiO4 |
| Mohs Hardness | 5 - 6 | 6.5 - 7 | 7.5 |
| Transparency | Opaque | Transparent | Transparent |
| Primary Source | Various (USA, Iran, etc.) | Tanzania (only source) | Sri Lanka, Brazil, Nigeria |
| Key Characteristic | Unique matrix patterns | Strong trichroism | Exceptional brilliance/fire |
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, the December birthstones are rich in symbolic meaning and are often associated with a range of metaphysical properties. These beliefs, while not scientifically proven, are deeply ingrained in the cultural history of the gems.
Turquoise is widely regarded as a stone of protection, healing, and good fortune. It is believed to shield the wearer from negative energy and harm. Many cultures, including Native American tribes, have considered it a sacred stone that connects the physical and spiritual worlds. It is also associated with tranquility, peace of mind, and emotional balance, making it a popular choice for meditation and spiritual practices.
Tanzanite, as a modern discovery, has quickly accumulated its own set of metaphysical associations. It is often called the "stone of transformation," believed to facilitate a higher consciousness, intuition, and spiritual perception. Its calming energy is said to promote compassion and a sense of calmness. Some also believe that Tanzanite can aid in detoxification and support the body's immune system, linking its healing properties to its vibrant life-giving color.
Zircon is associated with wisdom, clarity, and honor. It is believed to help its wearer achieve a clear mind and make wise decisions. Historically, it was also thought to promote sound sleep and ward off nightmares. The blue variety, in particular, is linked to tranquility and peace. Some beliefs also attribute to Zircon the power to attract wealth and prosperity, making it a symbol of abundance.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of any gemstone, and the December birthstones require specific attention due to their varying hardness and structural properties.
Turquoise is the most delicate of the three and demands the gentlest care. It should be protected from heat, chemicals, and sudden temperature changes, which can cause discoloration or cracking. To clean it, simply use warm water, a mild soap, and a soft cloth. Avoid ultrasonic cleaners and steam cleaners, as these can damage the stone. It is also wise to store Turquoise jewelry separately to prevent it from being scratched by harder gems.
Tanzanite requires careful handling due to its perfect cleavage, which makes it prone to splitting if knocked hard. It is not recommended for rings worn on the hand for daily activities. When cleaning, use warm soapy water and a soft brush, but be gentle. As with Turquoise, ultrasonic and steam cleaners are not safe for Tanzanite. It is best to store it in a soft cloth or padded jewelry box to prevent damage.
Zircon is the most durable of the December stones, but it can be brittle. While it is hard enough for everyday wear, it is still susceptible to chipping if subjected to a hard blow. Cleaning Zircon is relatively straightforward: warm soapy water and a soft brush are effective. It is generally safe to use an ultrasonic cleaner, but caution is advised if the stone has been fractured or filled. Steam cleaning is not recommended.
Conclusion
The December birthstones—Turquoise, Tanzanite, and Zircon—offer a remarkable trio of gems that celebrate the color blue in all its forms. From the ancient, opaque, and protective Turquoise to the rare, transformative, and violet-blue Tanzanite, and finally to the brilliant, wise, and sparkling Blue Zircon, each stone provides a unique narrative. Their diverse origins, distinct gemological properties, and rich symbolic meanings ensure that anyone born in December has a choice of gemstone that perfectly matches their personal style and story. Together, they form a harmonious and beautiful collection that captures the cool elegance and profound depth of the year's final month.