December is a month rich in tradition, symbolism, and celebration, and its gemstone lore reflects the same depth. It holds a unique distinction in the birthstone calendar: it is one of the few months with multiple official birthstones, a testament to the evolving nature of gemstone traditions and the diverse beauty found within the mineral kingdom. The December birthstones—Turquoise, Tanzanite, and Zircon—have been associated with the zodiac signs of Sagittarius and Capricorn, which span the month. These gemstones are not only admired for their beauty but also for the spiritual and historical significance they carry. From ancient talismans to modern jewelry, December birthstones offer a fascinating intersection of geology, astrology, and cultural heritage.
This article explores the zodiac associations of December’s birthstones, their gemological properties, their historical uses, and the beliefs that have shaped their meanings over time. Whether you are a gemstone enthusiast, a jewelry buyer, or a student of gemology, this guide provides an in-depth look at the December birthstones and their connections to the zodiac, grounded in the available historical and scientific records.
History and Lore
The concept of birthstones dates back centuries, with early records tracing to the Breastplate of Aaron, described in the Book of Exodus. This sacred Jewish artifact, worn by the High Priest, featured twelve gemstones representing the twelve tribes of Israel. Over time, these stones became associated with the zodiac and eventually with the months of the year, evolving into what we now recognize as birthstones.
December, as the final month of the year, has a particularly rich and varied history when it comes to its birthstones. The earliest known December birthstone was ruby, derived from ancient biblical interpretations. However, modern birthstone lists have evolved significantly. In 1870, turquoise was designated as the December birthstone by Tiffany & Co. in their "Gregorian Birthstone Poems." By 1912, turquoise remained primary, but lapis lazuli was also recognized as an alternative by the National Association of Jewelers. In 1952, zircon was added to the list, and in 2002, the American Gem Trade Association introduced tanzanite as a December birthstone, expanding the options for those born in this month. These changes reflect the dynamic nature of birthstone traditions, influenced by both cultural trends and the gemstone trade.
The Traditional Gem: Turquoise
Turquoise is the traditional and primary birthstone for December. Its name is derived from the French phrase pierre turquoise, meaning "stone of Turkey." This nomenclature arose because the stone was brought to Europe from Turkish bazaars, though its origins lie elsewhere. Historical evidence suggests that turquoise was mined and used as early as 7000 BCE in western Iran. It was a favored gem for amulets in many ancient cultures due to its relative ease of being cut into different shapes and inscribed upon. It was considered to have protective powers against danger and was expected to bring good fortune. Turquoise was prized by lovers and married couples as a gemstone protecting their relationships, and it was believed to preserve friendship if presented as a gift. A popular belief held that turquoise could warn its wearer of approaching illness or danger by becoming pale.
Various cultures have attributed profound significance to turquoise. Tibetans considered it a birthstone of fortune, health, and success, and the gem was often used as currency in Tibet. The ancient Incas and Mayas offered turquoise as a gift to their gods. For Native Americans of the Southwest, the gemstone was associated with youth and strength. Its sacred status in many cultures is well-documented, and it remains a symbol of protection, truth, and calmness.
The Modern Additions: Tanzanite and Zircon
While turquoise has the deepest historical roots, the modern list of December birthstones has expanded to include tanzanite and zircon, offering a broader palette of blue tones for those born in the month.
Tanzanite is a relatively new addition to the gemstone world, introduced as an official December birthstone in 2002 by the American Gem Trade Association. Its discovery in the 20th century and subsequent rise in popularity made it a fitting modern alternative, providing a vibrant violet-blue hue that differs from the classic sky-blue of turquoise.
Zircon, specifically blue zircon, was added to the official list in 1952. It is important to distinguish this natural blue zircon from the synthetic cubic zirconia often used in jewelry. Natural zircon is one of the oldest minerals on Earth, and its blue variety has been valued for centuries. The addition of zircon provided another durable and brilliant blue option for December babies.
Zodiac Connections
The zodiac signs attributed to December are Sagittarius (November 22–December 21) and Capricorn (December 22–January 20). Both signs contribute to the list of December birthstones, with specific gems often linked to enhancing the traits of each sign.
For Sagittarius, turquoise and tanzanite are particularly resonant. These stones are believed to amplify qualities like adventure, intuition, and a quest for truth, aligning with the archer's philosophical and free-spirited nature. For Capricorn, blue topaz and zircon are associated, supporting ambition, wisdom, and disciplined communication. Topaz, in particular, is noted as the main Zodiac birthstone for Sagittarius, with turquoise as a secondary stone. For Capricorn, the primary birthstone is ruby, but other December stones like blue topaz and zircon are also linked to this earth sign.
Geological Formation and Sources
Each of December’s birthstones has a unique geological origin, which influences its appearance, durability, and availability.
Turquoise
Turquoise is a secondary mineral formed by the interaction of acidic, copper-rich groundwater with minerals containing aluminum and phosphorus, such as feldspars or apatite. Over long periods, this groundwater seeps into the bedrock, and reactions with other minerals form an opaque stone of stunning shades of blues and greens. The dark lines and shapes seen in turquoise are derived from the surrounding rock, known as matrix. Major sources of turquoise include Iran, the United States (particularly Arizona and Nevada), Tibet, and India.
Blue Topaz
Blue topaz is a silicate mineral composed primarily of aluminum, fluorine, and silicon (Al₂SiO₄(F,OH)₂). Its blue color is the result of irradiation, a process that can occur naturally in the earth or be induced in laboratories to enhance the stone’s color. Blue topaz is typically found in pegmatite deposits and is one of the hardest December birthstones, with a Mohs hardness of 8. This makes it ideal for everyday wear and durable in jewelry. Blue topaz is most commonly mined in Brazil, the United States, Mexico, and Nigeria.
Zircon
Zircon (ZrSiO₄) is a mineral belonging to the group of nesosilicates. It is a common accessory mineral in igneous and metamorphic rocks. Natural blue zircon obtains its color through heat treatment of brown zircon crystals. Zircon is known for its high refractive index and strong dispersion, which gives it exceptional brilliance and fire. While zircon is found in many locations worldwide, specific sources for blue zircon are not detailed in the provided materials.
Tanzanite
Tanzanite is a variety of the mineral zoisite, colored by vanadium. It is found exclusively in a small area near Mount Kilimanjaro in Tanzania, which is the source of its name. The gem is known for its trichroism, displaying different colors—blue, violet, and burgundy—when viewed from different angles. Tanzanite is typically cut to show its dominant blue-violet hue.
Gemological Properties
Understanding the physical and chemical properties of these gemstones is crucial for their identification, valuation, and care. The following table summarizes key properties for the primary December birthstones, based on the provided sources.
| Gemstone | Mineral Group | Chemical Composition | Mohs Hardness | Typical Colors | Key Sources |
|---|---|---|---|---|---|
| Turquoise | Phosphate | Hydrated copper aluminum phosphate | 5 – 6 | Sky blue, greenish-blue | Iran, USA, Tibet, India |
| Blue Topaz | Silicate | Al₂SiO₄(F,OH)₂ | 8 | Blue (irradiated) | Brazil, USA, Mexico, Nigeria |
| Zircon | Nesosilicate | ZrSiO₄ | 6.5 – 7.5 | Blue (heat-treated) | Various (global) |
| Tanzanite | Zoisite (Group) | Ca₂Al₃(SiO₄)₃(OH) | 6.5 – 7 | Blue-violet, violet | Tanzania (exclusive) |
Turquoise is the softest of the group, with a Mohs hardness of 5 to 6. Its opacity and porosity require careful handling. Blue Topaz is notably hard, scoring an 8 on the Mohs scale, making it highly resistant to scratching and ideal for rings. Zircon and Tanzanite occupy a middle ground with hardnesses of 6.5 to 7.5 and 6.5 to 7, respectively. While durable, they are softer than topaz and require protection from sharp blows to prevent chipping or fracturing.
Color is a defining characteristic. Turquoise ranges from sky blue to greenish-blue, with its matrix patterns adding uniqueness. Blue topaz offers a consistent, often pale to medium blue. Blue zircon is prized for its brilliance and fire, while tanzanite provides a distinctive blue-violet hue that can shift depending on the light and viewing angle.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, December birthstones are steeped in symbolism and metaphysical beliefs that have persisted through centuries.
Turquoise is universally regarded as a stone of protection, truth, and calmness. It is believed to guard against negative energy and harm, making it a traditional amulet for travelers. Its association with friendship and fidelity is strong; gifting turquoise is thought to strengthen bonds and promote honest communication. In metaphysical practices, it is linked to the throat chakra, enhancing self-expression and creativity.
Blue Topaz is associated with calmness, communication, and emotional balance. Its name is sometimes linked to the Sanskrit word Tapas, meaning “fire,” suggesting a connection to inner strength and passion. It is believed to aid in clear thinking and articulate speech, making it a favored stone for those in professions requiring communication.
Zircon (blue) is often connected to wisdom, honor, and purity. Its brilliance is said to reflect a clear mind and spiritual insight. Historically, it was believed to promote prosperity and drive away evil spirits. Its high refractive index is metaphorically linked to an ability to see truth clearly.
Tanzanite, as a modern discovery, has quickly accrued its own lore. It is often called the "stone of transformation," believed to facilitate a higher consciousness and spiritual awakening. Its connection to Sagittarius enhances intuition and a quest for meaning, while its calming blue-violet tones are associated with relieving stress and anxiety.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these gemstones, and their differing hardnesses dictate specific cleaning methods.
Turquoise, due to its porosity and low hardness, is sensitive to chemicals, heat, and prolonged exposure to water. It should be cleaned with a soft, dry cloth. Avoid ultrasonic cleaners, steam cleaners, and harsh chemicals like ammonia or bleach, which can damage the stone and its protective treatments. Store turquoise separately to prevent scratching.
Blue Topaz, with its high hardness of 8, is quite durable and can be cleaned with warm water, mild soap, and a soft brush. It is resistant to most chemicals but should still be protected from extreme temperature changes. Ultrasonic cleaners are generally safe for untreated blue topaz, but caution is advised for stones with fractures.
Zircon (6.5–7.5 hardness) is relatively tough but can be brittle. It is best cleaned with warm, soapy water and a soft brush. Avoid sudden temperature shocks and ultrasonic cleaners, which could cause internal fractures to worsen. Store zircon separately to prevent scratching by harder gems.
Tanzanite (6.5–7 hardness) is sensitive to heat and pressure. It should never be exposed to steam or ultrasonic cleaners. The safest method is cleaning with warm, soapy water and a soft brush. Due to its cleavage (a tendency to break along flat planes), it should be handled with care to avoid sharp impacts.
For all gemstones, removing jewelry during activities like gardening, cleaning, or sports is recommended to prevent physical damage.
Conclusion
December's birthstones offer a remarkable diversity, from the ancient, opaque beauty of turquoise to the vibrant, modern brilliance of tanzanite and the fiery sparkle of blue zircon. Each stone carries a unique geological story, a rich tapestry of historical and cultural significance, and specific gemological properties that influence its use and care. Their connections to the zodiac signs of Sagittarius and Capricorn provide an additional layer of personal meaning, aligning their symbolic attributes with the traits of those born in the final month of the year.
Whether chosen for its traditional protective qualities, its striking color, or its astrological resonance, a December birthstone is more than a piece of jewelry; it is a link to a deep history of human belief and the enduring wonders of the mineral world. As the month of celebration and reflection, December is beautifully encapsulated in the cool, serene blues of its official gems.