December, the final month of the year, is uniquely distinguished by its possession of four official birthstones: turquoise, tanzanite, zircon, and blue topaz. This distinction sets it apart from other months, which typically feature only one or two gemstones. The multiplicity of birthstones for December is not merely an anomaly; it reflects the evolving nature of gemstone symbolism, availability, and cultural preferences over time.
This article delves into the rich history, geological properties, cultural significance, and practical care of each of these four December birthstones. By examining the role each gemstone plays in the world of jewelry and symbolism, we uncover the reasons behind their selection and how they contribute to the allure of December as a month of celebration and transformation.
History and Lore
The concept of birthstones is ancient and has evolved significantly over time. While the earliest known references to birthstones trace back to the Breastplate of Aaron in the Old Testament, the modern birthstone list was formalized in the early 20th century by the National Association of Jewelers (now the Jewelers of America). Since then, the list has seen several revisions, and December has been one of the most frequently updated months.
In 1870, the first official birthstone for December was designated as turquoise, inspired by a list compiled by Tiffany & Co. in the form of "Gregorian Birthstone Poems." By 1912, turquoise remained the primary December birthstone, but lapis lazuli was also listed as an alternative. In 1952, zircon was added to the list by the Jewelry Industry Council of America, and in 2002, tanzanite was officially recognized as the fourth December birthstone.
The inclusion of multiple birthstones for December reflects a growing emphasis on affordability and accessibility in the jewelry industry. As gemstones such as tanzanite and blue topaz gained popularity, they were added to the list to provide a wider range of options for consumers, particularly those who may not have been able to afford the traditional, often rarer, stones.
Each of these gemstones carries its own set of cultural and historical associations. Turquoise, for instance, has been revered for millennia across various civilizations, including the Egyptians, Chinese, and Native Americans. It was often used in amulets and talismans for protection and healing. Zircon, on the other hand, has a long history in ancient jewelry and is known for its brilliance and fiery luster. Tanzanite, a relatively modern discovery from Tanzania, quickly became a symbol of luxury and rarity. Blue topaz, while more affordable, is celebrated for its clarity and versatility in jewelry design.
Geological Formation and Sources
Understanding the geological origins of each of December’s birthstones offers insight into their rarity, coloration, and availability. These gemstones are formed under distinct geological conditions and are found in specific regions around the world.
Turquoise
Turquoise is a hydrated phosphate of aluminum and copper, with the chemical formula Al₂(OH)₃PO₄·4H₂O. It forms in the oxidation zones of copper deposits and is typically found in arid regions. The most historically significant sources of turquoise include Persia (modern-day Iran), Egypt, and the American Southwest, particularly in New Mexico and Arizona. The color of turquoise ranges from greenish-blue to deep blue, depending on the proportion of copper and iron present.
Turquoise is relatively soft, with a Mohs hardness of 5 to 6, making it more delicate compared to other gemstones. This softness means that it requires careful handling and is often stabilized with resin to enhance its durability.
Tanzanite
Tanzanite is a variety of the mineral columbite-zircon, chemically classified as CaAl₂(AlSiO₄)(OH)₂·H₂O, and is known for its trichroic properties, meaning it exhibits three different colors—blue, purple, and brown—depending on the angle of light. Tanzanite is exclusively found in Tanzania, in the Simanjiro district, near the Serengeti ecosystem and the Mount Kilimanjaro region. Discovered in 1967, tanzanite was officially introduced to the market in 1968, and it quickly gained popularity due to its vibrant color and rarity.
With a Mohs hardness of 6 to 6.5, tanzanite is relatively durable but still requires careful care to avoid scratches and damage. Its rarity—estimated to be 1,000 times less common than diamonds—makes it one of the most valuable December birthstones.
Zircon
Zircon is a zirconium silicate with the chemical formula ZrSiO₄. It is one of the oldest minerals on Earth, with some zircon crystals found in Australia dating back 4.4 billion years. Zircon is known for its high refractive index and dispersion, giving it a sparkling, diamond-like appearance when cut. Blue zircon is the most common variety used in jewelry and is produced through heat treatment.
Zircon is found in various parts of the world, including Burma (Myanmar), Thailand, Cambodia, and Madagascar. It has a Mohs hardness of 6 to 7.5, making it more durable than turquoise but less than tanzanite. Zircon was first added to the December birthstone list in 1952, replacing lapis lazuli, which had previously been an alternative.
Blue Topaz
Blue topaz is a silicate of aluminum and fluorine, with the chemical formula Al₂SiO₄(F,OH)₂. Naturally occurring blue topaz is extremely rare, so most blue topaz in the market is treated with irradiation or heat to enhance or create its blue color. The United States, Brazil, and Nigeria are the primary sources of topaz, with the state of Texas being a notable location for high-quality stones.
Blue topaz has a Mohs hardness of 8, making it one of the most durable of December’s birthstones. This durability, combined with its affordability and clarity, has made it a popular choice for everyday jewelry.
Gemological Properties
To appreciate the distinctiveness of each December birthstone, it is essential to examine their scientific properties, including color, clarity, cut, carat, and hardness.
| Gemstone | Color | Chemical Formula | Mohs Hardness | Origin |
|---|---|---|---|---|
| Turquoise | Blue to blue-green | Al₂(OH)₃PO₄·4H₂O | 5–6 | Iran, USA, Egypt |
| Tanzanite | Blue, purple, brown (trichroic) | CaAl₂(AlSiO₄)(OH)₂·H₂O | 6–6.5 | Tanzania |
| Zircon | Blue, yellow, brown | ZrSiO₄ | 6–7.5 | Burma, Thailand, Madagascar |
| Blue Topaz | Blue | Al₂SiO₄(F,OH)₂ | 8 | USA, Brazil, Nigeria |
Turquoise
Turquoise is a soft, porous stone with a waxy to greasy luster. It is often enhanced with resin or oil to improve its color and durability. Its color variation is a defining feature, and the most prized turquoise is deep blue with minimal green tones.
Tanzanite
Tanzanite is notable for its trichroism, which means it can display three colors when viewed from different angles. This effect is due to the crystal structure and the way light interacts with the stone. Tanzanite is also known for its high refractive index (1.69–1.70), which contributes to its sparkling appearance.
Zircon
Zircon is highly dispersive, meaning it splits light into a spectrum of colors, similar to a diamond. This gives it a "fire" or "sparkle" that is especially noticeable in well-cut stones. Zircon is also thermally sensitive, and improper heating can cause it to crack or change color.
Blue Topaz
Blue topaz is naturally colorless, and the blue color is usually induced through irradiation or heat treatment. The most popular blue topaz is Swiss blue, a deep blue-violet color. Blue topaz is also known for its clarity, often appearing very clean and transparent, making it ideal for large faceted stones.
Symbolism and Metaphysical Beliefs
Each of December’s birthstones is associated with a range of symbolic and metaphysical meanings, which vary across cultures and time periods.
Turquoise
Turquoise has long been considered a stone of protection, wisdom, and healing. In ancient Egypt, it was believed to ward off evil spirits and promote good health. Native American tribes, particularly the Navajo and Pueblo, used turquoise in ceremonial jewelry and as a protective charm. It is also associated with calmness, clarity, and emotional balance.
Tanzanite
Tanzanite is often linked to emotional transformation and spiritual awakening. It is believed to enhance intuition and psychic abilities, making it a popular stone for meditation and self-reflection. Tanzanite is also associated with love and compassion, and it is often used in healing practices to promote emotional healing and forgiveness.
Zircon
Zircon is known as a stone of prosperity and good fortune. It is believed to enhance personal power and confidence, and it is often used in amulets and talismans to attract wealth and success. Zircon is also associated with clarity of thought and emotional stability, making it a useful stone for decision-making and problem-solving.
Blue Topaz
Blue topaz is associated with calmness, wisdom, and self-expression. It is believed to soothe anxiety and promote a sense of peace and tranquility. Blue topaz is also linked to creativity and inspiration, making it a popular stone for artists and writers. It is considered a stone of honesty and truth, and it is often used in communication and conflict resolution.
Care and Cleaning
Given the varying hardness and composition of December’s birthstones, it is important to handle and clean them appropriately to preserve their beauty and longevity.
Turquoise
Turquoise is very soft and porous, so it should be avoided from exposure to water, oils, and chemicals. It should be cleaned with a dry, soft cloth and stored separately from harder gemstones to prevent scratches. Avoid ultrasonic cleaners and steamers, as they can damage the stone.
Tanzanite
Tanzanite is sensitive to heat and chemicals, so it should be avoided from high-temperature environments. It should be cleaned with a mild soap and warm water, using a soft brush to remove dirt and debris. Ultrasonic cleaners should be used with caution, and steam cleaning should be avoided.
Zircon
Zircon is heat-sensitive, and improper heating can cause it to crack or lose its color. It should be avoided from high-temperature environments, such as sunny windows or hot stoves. Zircon can be cleaned with a mild soap and water, using a soft brush, and it can also be cleaned with an ultrasonic cleaner, though steam cleaning should be avoided.
Blue Topaz
Blue topaz is one of the most durable December birthstones, with a hardness of 8 on the Mohs scale. It can be cleaned with a mild soap and warm water, using a soft brush or ultrasonic cleaner. It is relatively resistant to scratches and damage, making it suitable for daily wear.
Conclusion
December’s four birthstones—turquoise, tanzanite, zircon, and blue topaz—each bring their own unique beauty, history, and symbolism to the world of gemstones. The multiplicity of December’s birthstones reflects the evolving nature of the birthstone tradition, which has been shaped by cultural, economic, and aesthetic considerations over time.
Whether you are drawn to the ancient mystique of turquoise, the rare elegance of tanzanite, the sparkling brilliance of zircon, or the affordable charm of blue topaz, December offers a wide array of options for those seeking a gemstone that resonates with their birth month and personal style.
Understanding the history, properties, and care requirements of each of these gemstones allows you to make informed choices when selecting or caring for December’s birthstones, ensuring their beauty and value endure for generations.
Sources
- Frank Darling: 4 Reasons to Not Buy the Birthstone for December
- Gem Rock Auctions: December Birthstone
- The Ring Adviser: December Birthstones
- Tiny Rituals: December Birthstones
- The Gem Library: December Birthstones
- Moissanite by Aurelia: What Is December's Birthstone?
- Elasaro Jewelry Blog: December Birthstones