For those born in the final month of the year, the birthstone selection is uniquely expansive and visually striking. December is distinguished by having four recognized birthstones: Tanzanite, Zircon, Turquoise, and Blue Topaz. This abundance sets it apart from most other months, which typically have one or two official gems. The unifying theme among these four stones is their captivating blue hues, which evoke the crisp, serene, and icy aesthetics of winter. Each gemstone possesses its own distinct geological origin, historical narrative, and set of properties, offering December-born individuals a rich palette of choices for jewelry and personal adornment.
The modern birthstone list, as established by the Jewelers of America, officially recognizes three of these gems: Tanzanite, Zircon, and Turquoise. Blue Topaz, while immensely popular and frequently associated with December due to its cool color profile, is considered an emerging birthstone and is not yet included on the official list. This article will explore the history, geology, gemological properties, symbolism, and care requirements for each of these four remarkable December birthstones, drawing exclusively from authoritative sources to provide a comprehensive guide for enthusiasts, collectors, and jewelry buyers.
History and Lore
The historical journey of December's birthstones is as varied as the gems themselves, spanning centuries and continents. Turquoise stands as the original and most ancient of the group, long considered the primary December birthstone before the modern system was developed. Its lore is deeply rooted in protection and healing. For centuries, it has been treasured across numerous cultures, symbolizing protection, luck, and healing. This ancient reverence is evident in its widespread use in jewelry and artifacts from regions like the Middle East, Central Asia, and the Americas, where it was often worn as an amulet against harm and misfortune.
Zircon, another of the official December birthstones, carries its own historical weight. While specific ancient lore from the provided sources is limited, its status as a December birthstone is firmly established. It is important to note a common point of confusion: zircon is frequently mistaken for the synthetic diamond simulant cubic zirconia, but they are entirely different minerals. Natural zircon is one of the oldest minerals on Earth, and its use in jewelry dates back centuries.
Tanzanite's history is remarkably modern in comparison. Discovered in the 20th century, it is found exclusively in a single, small area of Tanzania, making it a geological rarity. Its rapid ascent to gemstone fame and its designation as a December birthstone are testaments to its unique color and appeal. The gemstone is celebrated for its captivating shades of blue and violet that appear to shift depending on the light, a phenomenon known as pleochroism.
Blue Topaz, while not officially on the December list, has a complex historical relationship with the month. Topaz itself is the traditional birthstone for November, but the blue variety has become strongly associated with December due to its cool, wintry hues. This association is largely a product of modern gemology and marketing, as most commercially available blue topaz is produced by irradiating naturally colorless topaz to achieve its deep blue color. Its name derives from the Sanskrit word for "fire," an irony given its most popular form is a cool blue.
Geological Formation and Sources
The geographic origins of these birthstones are as diverse as their histories, ranging from ancient, globally distributed minerals to a gemstone found in only one location on Earth.
Turquoise is a hydrous phosphate of copper and aluminum. It forms in arid regions where acidic, copper-rich groundwater seeps through pre-existing rocks and reacts with minerals containing aluminum and phosphorus. Over time, this process creates veins and nodules of turquoise. While major historical sources include Persia (modern-day Iran) and the American Southwest, the provided sources do not specify current mining locations. Its formation is intrinsically linked to specific geological conditions, making it a relatively rare and localized mineral.
Zircon is a zirconium silicate (ZrSiO₄) and is a common accessory mineral found in many igneous and metamorphic rocks. It is widely distributed across the globe, with significant deposits in countries such as Australia, Sri Lanka, Thailand, and Cambodia. Its durability and resistance to weathering allow it to survive in sedimentary deposits, making it accessible in many regions.
Tanzanite is the most geographically restricted of all December's gems. It is found only in the Merelani Hills of Northern Tanzania, a small mining area near the base of Mount Kilimanjaro. This exclusive origin contributes to its rarity and value. The gem is a variety of the mineral zoisite, and its formation is linked to specific metamorphic processes in this unique geological setting.
Blue Topaz is a silicate mineral composed of aluminum and fluorine. While topaz crystals can be found in various locations worldwide, including Brazil, Pakistan, and Sri Lanka, the natural blue variety is exceedingly rare. The vast majority of blue topaz in the market begins as colorless topaz, which is then treated through irradiation to induce a blue color. The sources indicate that its color range spans from dark inky blues to cooler light blue shades, with commercial varieties including London Blue, Swiss Blue, and Sky Blue topaz.
Gemological Properties
Understanding the physical and optical properties of these gems is crucial for identification, valuation, and care. The following table summarizes key gemological data for each December birthstone based on the provided sources.
| Gemstone | Chemical Composition | Hardness (Mohs Scale) | Key Characteristics | Notable Varieties |
|---|---|---|---|---|
| Tanzanite | Calcium Aluminum Silicate Hydroxide (Zoisite) | Not specified in sources | Exhibits strong pleochroism (shifts between blue, violet, and purple); found only in Tanzania. | N/A |
| Zircon | Zirconium Silicate (ZrSiO₄) | Not specified in sources | One of the oldest minerals on Earth; often confused with cubic zirconia. | N/A |
| Turquoise | Hydrous Copper Aluminum Phosphate | Not specified in sources | Known for its vibrant blue-green hue and unique veining (matrix). | N/A |
| Blue Topaz | Aluminum Silicate with Fluorine | 8 (Mohs) | Good durability; color is typically enhanced via irradiation of colorless topaz. | London Blue (deep inky blue), Swiss Blue (vibrant medium light blue), Sky Blue (light aqua) |
Tanzanite is renowned for its intense and unique color play. Its pleochroic nature means it can show different colors—typically blue, violet, and purple—from different crystallographic directions. This property makes the cut of the gemstone critical to maximizing its visual appeal. While the sources do not specify its hardness, it is generally known in gemology to have a hardness of 6.5 to 7 on the Mohs scale, making it suitable for jewelry with appropriate care.
Zircon is a highly durable gemstone, though the provided sources do not list its specific hardness. It is known for its high refractive index and strong dispersion (fire), which gives it a brilliance comparable to that of a diamond. Its color range is extensive, but the blue variety is specifically associated with December.
Turquoise is an opaque gemstone with a distinctive waxy to vitreous luster. Its color is typically blue to blue-green, and it often contains a dark, spiderweb-like matrix of the host rock, which is considered part of its character. As an opaque stone, its value is influenced more by color and uniformity than by clarity in the same way as transparent gems.
Blue Topaz is notable for its hardness of 8 on the Mohs scale, which makes it quite durable and suitable for a variety of jewelry types, including rings that are worn daily. It is a transparent gemstone with a glass-like luster. As mentioned, its deep cleavage can make it somewhat delicate despite its hardness, requiring careful cutting and setting. The color varieties are primarily defined by the intensity and shade of blue, with London Blue being the most valued for its saturated, deep hue.
Symbolism and Metaphysical Beliefs
The symbolic meanings attributed to these birthstones are as varied as their colors, drawing from both ancient traditions and modern interpretations.
Turquoise carries the most extensive symbolic history. Across cultures, it has been revered as a stone of protection, luck, and healing. It is often associated with tranquility, serenity, and balance, believed to ward off negative energy and promote well-being. Its connection to the sky and water in many cultures reinforces these themes of peace and clarity.
Tanzanite, as a relatively new gem, has developed modern symbolic associations. It is often linked to positivity, truth, and spiritual awakening. Its captivating color shift is sometimes interpreted as a metaphor for seeing the world from different perspectives or for a higher state of consciousness. Its exclusive origin in Tanzania adds an element of rarity and specialness to its symbolism.
Zircon is traditionally associated with wisdom, honor, and purity. In some beliefs, it is thought to promote prosperity and honor, and to help the wearer achieve their goals. Its durability and ancient nature lend it a symbolism of strength and endurance.
Blue Topaz, particularly in its cool blue forms, symbolizes wisdom, honesty, and calm communication. Its icy glacial tones are linked to clarity of thought and emotional balance. It is often seen as a stone that aids in expressing one's truth with compassion and clarity. The connection to November's topaz (symbolizing friendship and love) extends to blue topaz as well, representing loyal and honest affection.
Care and Cleaning
Proper maintenance is essential to preserve the beauty and longevity of any gemstone jewelry. The care requirements for December's birthstones vary significantly based on their physical properties.
Tanzanite requires careful handling due to its relative softness (Mohs 6.5-7) and perfect cleavage in one direction. It should be protected from hard blows, sharp temperature changes, and harsh chemicals. Cleaning can be done with warm, soapy water and a soft brush, but ultrasonic and steam cleaners should be avoided. It is best suited for earrings, pendants, and occasional-wear rings.
Zircon is a durable stone but can be brittle due to its crystal structure. It is resistant to heat and chemicals but should be protected from sharp blows. Warm, soapy water and a soft brush are safe for cleaning. As with tanzanite, avoid ultrasonic cleaners.
Turquoise is an opaque, porous stone that is sensitive to chemicals, cosmetics, and even skin oils. It should be cleaned only with a soft, dry cloth. Avoid submerging it in water or using any chemical cleaners, as this can damage the stone and alter its color. It is best to put on turquoise jewelry after applying lotions and perfumes.
Blue Topaz, with its hardness of 8, is quite durable for everyday wear. However, its deep cleavage means it can be chipped by a hard blow. It is generally safe to clean with warm, soapy water and a soft brush. It is also resistant to most chemicals and heat, making it a practical choice for various jewelry settings. While it can be worn daily, it is still advisable to remove it during strenuous activities to prevent impact damage.
Conclusion
The four birthstones of December—Tanzanite, Zircon, Turquoise, and Blue Topaz—offer a remarkable spectrum of beauty, history, and meaning. From the ancient, protective lore of Turquoise to the modern exclusivity of Tanzanite, the enduring fire of Zircon, and the commercially popular cool tones of Blue Topaz, each gem provides a unique connection to the winter month. Their shared blue color palette unites them as symbols of serenity and purity, while their individual characteristics cater to a wide range of personal tastes and lifestyles. Whether chosen for their symbolic significance, geological rarity, or simply their stunning visual appeal, these four gems ensure that anyone born in December has a wealth of exquisite options to celebrate their birth month. Understanding their distinct properties and care requirements allows for a deeper appreciation and ensures these beautiful stones can be cherished for generations.