December is a month of celebration and reflection, marked by the cool, serene hues of its birthstones. The traditional December birthstone is turquoise, a semi-translucent to opaque gem cherished for millennia. Modern alternatives include tanzanite, known for its violet-blue color, and zircon, prized for its diamond-like brilliance and range of colors, including a popular icy blue. These stones reflect the winter landscape and are associated with serenity, wisdom, and protection. The primary stone, turquoise, holds deep historical and cultural significance, while tanzanite and zircon offer contemporary elegance and symbolic meaning. This article explores the rich history, geological origins, gemological properties, and cultural symbolism of these remarkable gems, providing a comprehensive guide for enthusiasts, buyers, and students of gemology.
History and Lore
The history of December’s birthstones spans continents and millennia, with each stone carrying a unique narrative of human culture and belief.
Turquoise is arguably one of the oldest known gemstones in use. Its name derives from the French pierre turquoise, meaning "Turkish stone," as it was brought to Europe from the Middle East through Turkey. However, its origins are far older. Chinese artisans carved turquoise more than 3,000 years ago. The gemstone was highly prized in ancient Egypt, where pharaohs and other rulers adorned themselves with it. It was believed to possess beneficial powers, such as guaranteeing health and good fortune. From the 13th century onward, a widespread European belief held that turquoise could protect the wearer from falling, particularly from horses, and that it would break into several pieces to signal an approaching disaster. Hindu mystics maintained that seeing a turquoise after beholding the new moon ensured fantastic wealth. In Native American cultures, particularly among the Apache, turquoise was thought to be found by following a rainbow to its end, and it remains a sacred stone in many indigenous traditions. Its primary significance is tied to friendship, protection, and good fortune.
Zircon has a long and storied history, often confused with the much less valuable cubic zirconia. The word "zircon" may come from the Persian zargun, meaning "gold-colored." Historically, zircon was associated with wisdom, honor, and purity. It was believed to bring peace and prosperity to its wearer. In the Middle Ages, zircon was used to protect against poisoning and illness. Its fiery brilliance led to its association with light and clarity. As a modern birthstone, zircon is linked to clarity, wisdom, and a sense of balance.
Tanzanite is the newest of the three, discovered in the mid-20th century. Its history is brief but impactful. It was first identified in the Merelani Hills of Tanzania in 1967 and named by Tiffany & Co. after the country of its origin. Its rapid rise to prominence was fueled by its unique color and the marketing efforts of Tiffany. In terms of symbolism, tanzanite represents transformation and new beginnings, making it a popular choice for significant life events and gifts.
The journey to their status as December birthstones is also noteworthy. The modern list of birthstones was standardized in 1912 by the National Association of Jewelers (now Jewelers of America), with turquoise as the official stone. Zircon was added as a modern alternative, and tanzanite was included in 2002, making it one of the newest additions to the birthstone calendar. The presence of multiple stones for December is intentional, offering a variety of colors and styles to suit personal preference.
Geological Formation and Sources
Each of these gemstones forms under specific geological conditions and is sourced from distinct regions of the world.
Turquoise is a phosphate mineral, specifically a hydrated copper and aluminum phosphate. It forms in arid regions where acidic, copper-rich groundwater seeps through and reacts with rocks containing aluminum and phosphorus. Over long periods, this process creates turquoise nodules or veins. Major sources mentioned in the provided materials include Iran (historically the source of the finest "Persian turquoise" with its intense sky-blue color and little to no matrix), the USA (notably Nevada and Arizona, producing stones with characteristic black or brown matrix webbing), Tibet (known for greenish-blue tones with a webbed matrix pattern), and India. The presence of matrix—the host rock in which the turquoise formed—is a key identifier of its origin and affects its appearance and value.
Zircon is a zirconium silicate (ZrSiO₄) and is one of the oldest minerals on Earth, found in many igneous, metamorphic, and sedimentary rocks. It forms during the crystallization of magma and is highly resistant to weathering, which is why it is often found in alluvial deposits (riverbeds and coastal areas). The blue variety of zircon, which is popular for December, is typically produced by heat-treating brown or colorless zircon. Major sources for zircon include Sri Lanka, Cambodia, and Australia. Sri Lankan zircon, in particular, is known for its high-quality blue stones.
Tanzanite is a variety of the mineral zoisite, specifically the blue to violet-blue form caused by vanadium impurities. It is found exclusively in a small, four-square-kilometer area in the Merelani Hills of Tanzania, near the base of Mount Kilimanjaro. This extremely limited geographic source makes tanzanite one of the rarest gemstones. The formation of tanzanite is linked to a unique geological event where intense heat and pressure altered the zoisite crystals, creating the vibrant blue color. The material is mined in Tanzania and is almost always heat-treated to enhance its color to the desirable violet-blue hue.
Gemological Properties
Understanding the physical and chemical properties of these stones is crucial for identification, valuation, and care. The following table summarizes key gemological data for the December birthstones, based on the provided sources.
| Property | Tanzanite | Turquoise | Zircon | Blue Topaz |
|---|---|---|---|---|
| Mineral Group | Zoisite (Variety) | Phosphate | Zirconium Silicate | Silicate |
| Chemical Formula | Ca₂(Al,OH)₂(SiO₄)₃ | CuAl₆(PO₄)₄(OH)₈·4H₂O | ZrSiO₄ | Al₂SiO₄(F,OH)₂ |
| Mohs Hardness | 6 to 7 | 5 to 6 | 6.5 to 7.5 | 8 |
| Crystal System | Orthorhombic | Triclinic | Tetragonal | Orthorhombic |
| Common Treatments | Heat Treatment | Stabilization, Dyeing | Heat Treatment | Heat Treatment |
| Natural Color | Blue to violet | Sky blue to greenish | Blue (heat-treated) | Pale blue to dark blue |
| Key Sensitivity | Prone to chipping | Sensitive to chemicals | Brittle at edges | Sensitive to sharp impacts |
Turquoise has a Mohs hardness of 5 to 6, making it relatively soft and susceptible to scratching and chipping. It is also porous and can be sensitive to chemicals, perfumes, and prolonged exposure to moisture, which can cause discoloration. Most commercial turquoise is stabilized (impregnated with a clear resin) to improve durability and color. Its color ranges from sky blue to greenish-blue, often with a characteristic matrix pattern.
Zircon is harder, with a Mohs hardness of 6.5 to 7.5, making it more durable for jewelry than turquoise. However, it can be brittle, especially at the edges, and is prone to chipping if struck. Natural blue zircon is rare; most blue zircon on the market is produced by heating brown zircon. It has a high refractive index, giving it a brilliant, diamond-like sparkle. Its color is typically a bright, clear blue.
Tanzanite has a Mohs hardness of 6 to 7, but it is brittle and can chip easily, especially along cleavage planes. It is not recommended for rings worn daily unless set in a protective setting. Its most striking feature is its pleochroism—showing different colors (blue, violet, and burgundy) when viewed from different angles. The rich violet-blue color is almost always achieved through heat treatment. Its limited source in Tanzania makes it a rare and valuable gem.
Blue Topaz, while not a traditional December birthstone, is frequently mentioned as a modern alternative. It has a Mohs hardness of 8, making it very durable and suitable for all types of jewelry, including daily-wear rings. Most blue topaz is colorless topaz that has been irradiated and heat-treated to achieve its blue hue. The color ranges from pale sky blue to deep London Blue.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, December’s birthstones are imbued with deep symbolic and metaphysical meanings, which have evolved over centuries.
Turquoise is universally recognized as a stone of protection. Ancient cultures believed it could safeguard the wearer from harm, violence, and accidents. It is also associated with communication, truth, and calmness, helping to balance emotions and promote inner peace. In many traditions, it is a stone of friendship, fostering loyalty and trust. Its connection to the earth and sky makes it a grounding yet spiritually uplifting gem.
Zircon is linked to clarity of thought, wisdom, and intuition. It is believed to enhance spiritual awareness and bring peace and prosperity. Historically, it was thought to promote honor and purity. In modern crystal healing, blue zircon is associated with the throat chakra, aiding in clear communication and self-expression.
Tanzanite, as a modern discovery, carries contemporary symbolism. It is often called the "stone of transformation," believed to facilitate major life changes, spiritual awakening, and new beginnings. Its energy is considered calming and soothing, helping to alleviate stress and anxiety. It is also associated with enhancing intuition and psychic abilities. For Capricorns, in particular, it is said to support ambition and emotional healing.
The planetary associations for December birthstones are Jupiter and Saturn, which rule the zodiac signs of Sagittarius (Nov 22 – Dec 21) and Capricorn (Dec 22 – Jan 19). Turquoise is often recommended for Sagittarius, aligning with their honest and dynamic energy, while tanzanite is suited for Capricorn, aiding their focus and clarity.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these gemstones, given their varying physical properties.
Turquoise requires the gentlest care. Due to its porosity and softness, it should be cleaned only with warm, soapy water and a soft brush. Avoid all chemicals, including household cleaners, perfumes, and cosmetics, as they can damage or discolor the stone. It should also be protected from prolonged exposure to moisture and extreme temperatures. Store it separately to avoid scratches.
Zircon is harder but brittle. It can be cleaned with warm soapy water and a soft brush. Avoid ultrasonic cleaners and steam cleaning, as the heat and vibrations can cause fractures. It is also sensitive to sharp impacts, so protective settings are recommended for rings.
Tanzanite is delicate and prone to chipping. Clean it with warm, soapy water and a soft cloth. Avoid ultrasonic cleaners, steam cleaning, and harsh chemicals. Due to its brittleness, it is best set in protective settings like pendants, earrings, or occasional-wear rings rather than daily-wear rings.
Blue Topaz is relatively durable and can be cleaned with warm soapy water and a soft brush. While it can withstand mild ultrasonic cleaning, it is best to avoid harsh impacts, as sharp knocks can chip the stone, especially at facet edges.
Conclusion
December’s birthstones offer a captivating array of colors, histories, and meanings. Turquoise, with its ancient heritage and protective symbolism, remains the traditional cornerstone. Zircon provides brilliant sparkle and durability, while tanzanite brings a rare, modern elegance with its transformative energy. Each stone, from the earthy matrix of turquoise to the shifting blues of tanzanite and the fiery brilliance of zircon, holds a unique place in the world of gemology. Understanding their origins, properties, and care requirements allows enthusiasts and buyers to make informed choices, ensuring these winter-born gems can be cherished for generations. Whether chosen for their beauty, historical significance, or metaphysical properties, the December birthstones are a testament to the enduring allure of the mineral kingdom.