December is unique among the months in the birthstone calendar, distinguished by the inclusion of multiple gemstones—each offering a distinct shade, history, and symbolism. The primary and traditional December birthstone is Turquoise, while Tanzanite, Zircon, and more recently Blue Topaz have also been officially recognized as December birthstones. These gemstones are all connected by their blue hues, which reflect the cool tones of winter and the calm, contemplative nature often associated with the end of the calendar year.
This article explores the color, symbolism, geological properties, historical significance, and practical considerations of these December birthstones. Drawing from authoritative sources in gemology, trade publications, and historical records, we provide a comprehensive overview of these captivating gems, from their origins in the earth to their enduring place in jewelry and cultural traditions.
Historical Significance and Cultural Lore
The tradition of associating specific gemstones with birth months is ancient, with roots in biblical and medieval European traditions. The earliest known reference to birthstones comes from the Breastplate of Aaron in the Old Testament (Exodus 39:14), which lists 12 stones, although their identification has long been debated.
For December, the most historically recognized birthstone is Turquoise. The name "Turquoise" derives from the French pierre turquoise, meaning "Turkish stone," a reference to the trade route through which it was introduced to Europe from the East. However, the use of turquoise dates back thousands of years. It was highly valued by ancient civilizations such as the Egyptians, who used it in jewelry and amulets for protection and good fortune. Native American cultures also revered turquoise as a sacred stone, often incorporating it into jewelry and ritual items.
The addition of Zircon and Tanzanite as December birthstones is a more modern development. Zircon has been used in jewelry for centuries, though it was only officially recognized as a December birthstone in 1952 by the Jewelry Industry Council of America. Tanzanite, a relatively recent discovery, was added in 2002 due to its unique properties and rarity. Blue Topaz, while not as ancient as the others, is increasingly popular in modern jewelry and was added to the December birthstone list as a durable and affordable option.
These multiple gemstone designations for December reflect both historical tradition and contemporary commercial and aesthetic preferences. The variety allows for greater flexibility in jewelry design and personal choice, especially considering the differing hardness and durability of each stone.
Geological Formation and Mining Origins
The December birthstones are all formed under unique geological conditions, and their locations of origin contribute to their rarity and value.
Turquoise
Turquoise is a phosphate mineral formed by the interaction of groundwater rich in copper with other minerals in the rock. This process, which occurs over long periods, results in an opaque stone with a range of colors from deep blue to greenish-blue. The characteristic matrix lines and patterns visible in turquoise are derived from the surrounding rock in which it forms.
Major sources of turquoise include Iran, the United States (particularly the Southwestern states like Arizona and New Mexico), Tibet, and India. The most prized turquoise, known for its intense blue color and minimal matrix, is often found in the Persian (Iranian) and American Southwest regions.
Turquoise has a Mohs hardness of 5–6, making it relatively soft compared to other gemstones. As a result, it is more susceptible to scratches and requires careful handling and cleaning.
Tanzanite
Discovered in 1967 in Tanzania, Tanzanite is a variety of the mineral zoisite that exhibits a trichroic nature, meaning it can display three different colors—blue, purple, and brown—depending on the angle of light. This unique optical property makes it one of the most distinctive gemstones.
Tanzanite is formed under high pressure and temperature in the presence of titanium, which gives it its characteristic violet-blue color. It is mined in a very limited area of Northern Tanzania, near the Serengeti National Park and Mount Kilimanjaro, which contributes to its rarity and high value.
With a Mohs hardness of 6–7, Tanzanite is relatively fragile, especially along the direction of its cleavage. This makes it less suitable for everyday wear without proper protection and setting.
Zircon
Zircon is a zirconium silicate mineral that occurs in a wide range of colors, from colorless to yellow, red, and blue. The blue variety, known as Blue Zircon, is the December birthstone. It is formed in metamorphic and igneous rocks and is often found in alluvial deposits, where it has been naturally separated from other minerals.
Blue Zircon is typically created through heat treatment, which enhances its blue color and gives it a glassy luster. Zircon is found in various parts of the world, including Australia, Brazil, India, and Thailand.
Zircon has a Mohs hardness of 6.5–7.5, making it more durable than Turquoise and Tanzanite. However, it is still relatively fragile compared to harder gemstones like sapphires or diamonds, and care should be taken when handling or cleaning Zircon jewelry.
Blue Topaz
Blue Topaz is a silicate mineral that is naturally colorless but is often irradiated and heat-treated to produce its deep blue hues. The coloration process enhances its visual appeal and gives it a glass-like luster.
Blue Topaz is found in several countries, including Brazil, Nigeria, Mexico, and the United States. It is particularly abundant in Brazil, where it is often mined in large quantities.
With a Mohs hardness of 8, Blue Topaz is the hardest and most durable of the December birthstones, making it an excellent option for everyday wear and jewelry that is worn frequently. Its durability and affordability have contributed to its growing popularity in modern jewelry design.
Gemological Properties and Aesthetic Appeal
Each of December’s birthstones has distinct gemological properties that influence their use in jewelry and their appeal to collectors and consumers.
Color
All four December birthstones are characterized by blue hues, though the exact shade varies. Turquoise ranges from sky blue to greenish-blue, often with matrix patterns that add visual interest. Zircon typically has a bright, clear blue that is vibrant and eye-catching. Tanzanite is known for its rich, deep violet-blue that can shift subtly in different lighting. Blue Topaz comes in a range of blue shades, from the light, sky-blue of Swiss Blue to the deep, inky blue of London Blue.
Hardness and Durability
The hardness of a gemstone determines its resistance to scratches and abrasion, which is crucial for jewelry that is worn regularly. Blue Topaz, with a Mohs hardness of 8, is the most durable of the four. Zircon follows with a hardness of 6.5–7.5, while Tanzanite and Turquoise are softer, with hardness ratings of 6–7 and 5–6, respectively.
Durability also depends on the internal structure of the gemstone. Tanzanite has cleavage, making it prone to chipping or breaking along specific planes. Turquoise is porous and soft, and it can absorb oils and fragrances, which may alter its appearance over time.
Luster and Transparency
The luster and transparency of a gemstone also contribute to its visual appeal. Turquoise has a waxy to dull luster, while Zircon and Tanzanite exhibit a glassy to vitreous luster. Blue Topaz has a highly glassy luster, especially in its treated varieties, which can closely resemble the sparkle of a diamond.
In terms of transparency, Turquoise is opaque, while Zircon, Tanzanite, and Blue Topaz can be transparent to translucent, depending on the quality and treatment of the stone.
Cut and Shape
The cut and shape of a gemstone are also important considerations in jewelry design. Turquoise is often cut into cabochons (smooth, rounded shapes) to enhance its surface patterns and color depth. Zircon, Tanzanite, and Blue Topaz are typically cut into faceted shapes, such as brilliant cuts, emerald cuts, and ovals, to maximize their brilliance and fire.
Symbolism and Metaphysical Beliefs
The December birthstones are not only prized for their beauty and rarity but also for the symbolism and metaphysical properties attributed to them. These beliefs vary across cultures and historical periods, but several recurring themes are associated with each stone.
Turquoise
Turquoise has long been associated with protection, healing, and spiritual wisdom. In ancient cultures, it was believed to ward off evil spirits and bring good fortune. It was also used in amulets and talismans to protect travelers and warriors.
In Native American traditions, turquoise is considered a sacred stone that connects the earth and sky. It is often used in ceremonial jewelry and is believed to bring harmony and balance. In Chinese and Persian cultures, turquoise was used in jewelry and decorative objects as a symbol of immortality and prosperity.
Tanzanite
Tanzanite is often associated with transformation, intuition, and emotional balance. It is believed to help individuals navigate change and uncertainty with calm and confidence. In New Age and metaphysical practices, Tanzanite is said to open the heart and throat chakras, promoting clarity, communication, and emotional healing.
Its rarity and uniqueness also make it a symbol of individuality and self-discovery. Some believe that Tanzanite helps the wearer connect with their higher self and spiritual path.
Zircon
Zircon is associated with wisdom, clarity, and spiritual awakening. In ancient times, it was believed to protect the wearer from negative energies and promote inner strength. It is also associated with dreams and intuition, and some traditions suggest that it can enhance psychic abilities and mental clarity.
Zircon is also linked to the power of fire, especially in its yellow and red varieties, which are believed to stimulate creativity and energy. In modern metaphysical practices, Blue Zircon is used to calm the mind and reduce stress, making it a popular stone for meditation and relaxation.
Blue Topaz
Blue Topaz is believed to promote serenity, calmness, and emotional balance. It is associated with the throat chakra, which governs communication and self-expression. Some believe that Blue Topaz helps individuals speak their truth with confidence and clarity.
It is also thought to attract love and friendship, making it a popular stone for relationships and social connections. In Western traditions, Blue Topaz is also associated with good fortune and protection, especially when worn as a ring or pendant.
Care and Cleaning
Due to the varying hardness, porosity, and cleavage of the December birthstones, proper care and cleaning are essential to maintaining their beauty and longevity.
Turquoise
Turquoise is soft and porous, and it can absorb oils, lotions, and perfumes, which may alter its color and surface over time. It should be stored separately from other gemstones to avoid scratches and should be avoided in harsh environments, such as chlorine or salt water.
Cleaning should be done with a soft cloth and mild soap and water. Ultrasonic cleaners and steam cleaners should be avoided, as they can damage the stone.
Tanzanite
Tanzanite is sensitive to heat and light, and prolonged exposure may alter its color. It should be stored in a cool, dark place when not in use.
Cleaning can be done with a soft cloth and mild soap and water. Ultrasonic cleaners can be used with caution, but steam cleaners and harsh chemicals should be avoided.
Zircon
Zircon is more durable than Turquoise and Tanzanite, but it is still susceptible to scratches and damage. It should be stored separately from harder gemstones and handled with care.
Cleaning can be done with a soft cloth and mild soap and water. Ultrasonic and steam cleaners can be used with caution, especially with heated and irradiated varieties, as they may be more delicate.
Blue Topaz
Blue Topaz is the most durable of the December birthstones, with a Mohs hardness of 8, making it suitable for everyday wear. It is resistant to scratches and abrasion, but it can still be damaged by harsh chemicals.
Cleaning can be done with a soft cloth and mild soap and water, and ultrasonic and steam cleaners can be used with caution, depending on the quality and treatment of the stone.
Conclusion
December’s birthstones—Turquoise, Tanzanite, Zircon, and Blue Topaz—offer a rich tapestry of history, symbolism, and gemological properties. Each gemstone is associated with unique colors, origins, and meanings, making them versatile and meaningful choices for jewelry and personal adornment.
Whether you choose Turquoise for its ancient wisdom and protection, Tanzanite for its rare beauty and transformative power, Zircon for its clarity and spiritual insight, or Blue Topaz for its durability and serenity, each December birthstone carries a distinct legacy and charm.
As the only month with four official birthstones, December reflects the diversity and richness of gemstone traditions, combining ancient beliefs with modern aesthetics. The inclusion of multiple options allows for greater personalization and flexibility, ensuring that everyone born in December can find a stone that resonates with their style, values, and identity.