December is unique in the world of birthstones. While most months are assigned a single gem, December boasts a trio of distinct and captivating stones: Turquoise, Tanzanite, and Zircon. This abundance of choice offers a spectrum of blue, from the sky-like softness of Turquoise to the deep, velvety violet-blue of Tanzanite and the brilliant fire of Zircon. Each stone carries its own rich history, geological origins, and symbolic weight, providing a wealth of options for those born in the final month of the year. This guide delves into the science, history, and lore of these three official December birthstones, exploring what makes each one a treasured gem.
A Legacy of Protection and Transformation
The history of December's birthstones is a fascinating blend of ancient tradition and modern discovery. Turquoise, the most venerable of the trio, has been cherished for millennia. Its name offers a clue to its journey into Western culture; it derives from the French phrase pierre turquoise, meaning "stone of Turkey." This is because the gem was brought to Europe from Turkish bazaars, though its origins lie far from there. Historically, Turquoise has been a talisman of protection and good fortune, a belief held across numerous cultures. It is described as a sacred stone in many traditions, deeply associated with friendship, truth, and calmness. Its enduring appeal lies in its distinctive color and the unique, often intricate, matrix patterns that run through the opaque stone.
In stark contrast to Turquoise's ancient lineage, Tanzanite is a thoroughly modern discovery. It entered the gemological world in 1967, making it one of the youngest gems to achieve such prominence. Found in a single, small area of Tanzania—hence its name—this blue variety of zoisite quickly captured the market with its rich, saturated color and pleochroic properties, which display different hues of blue and violet when viewed from various angles. The International Colored Gemstone Association (ICA) recognizes it as one of the most important gemstone discoveries of the 20th century. Its symbolism is tied to its modernity, often representing transformation, new beginnings, and a forward-looking perspective. Its inclusion as an official birthstone came in 2002, a testament to its rapid rise in popularity and cultural acceptance.
Zircon, the third member of the trio, holds a dual identity in the gem world. It is one of the oldest known minerals on Earth, with zircon crystals found in Australia dating back over 4.4 billion years. Yet, it is often misunderstood due to its phonetic similarity to the synthetic cubic zirconia. True zircon is a natural gemstone prized for its exceptional brilliance and fire, which rival that of diamond. The blue variety, which is the designated birthstone, is particularly valued. The journey of zircon to its birthstone status is a story of evolving lists. The modern standardization of birthstones began in 1912 by the National Association of Jewelers. This list has been updated over the years; zircon was officially added to December's list in 1952 by the Jewelry Industry Council of America. Its symbolism is often linked to clarity, wisdom, and a sense of balance, reflecting its sharp faceting and clear appearance.
The proliferation of December's birthstones is a subject of interest. While the traditional list includes Turquoise and Zircon, the modern list has expanded to include Tanzanite and, frequently, Blue Topaz. Some sources suggest this variety was intentional, offering consumers more options in terms of color, style, and price. The addition of new stones as they are discovered or gain commercial traction reflects the dynamic nature of birthstone traditions.
The Science of the Blue Spectrum
While all three stones are celebrated for their blue hues, their chemical compositions, physical properties, and geological origins are entirely different. Understanding these gemological characteristics is key to appreciating and caring for each stone.
Turquoise
Turquoise is an opaque phosphate mineral that owes its color to the presence of copper. Traces of iron can shift the color toward a greenish hue, while the presence of zinc can create a yellowish tint. The distinctive dark veins and blotches, known as matrix, are remnants of the host rock in which the Turquoise formed. This matrix is not a flaw but rather an integral part of the stone's character, often used by gemologists to help identify its origin.
- Mohs Hardness: 5 to 6. This relatively low hardness makes Turquoise susceptible to scratches and damage from chemicals. It is not ideal for daily wear in rings unless set in a protective mounting.
- Major Origins: Historically significant sources include Iran, Tibet, and the southwestern United States (specifically Arizona and New Mexico). India is also listed as a source country.
Tanzanite
Tanzanite is a variety of the mineral zoisite. Its mesmerizing violet-blue color is the result of trace amounts of vanadium within its crystal structure. Unlike Turquoise, Tanzanite is typically a transparent gemstone, valued for its clarity and deep color saturation. It is strongly pleochroic, a property where a gem shows different colors when viewed from different directions. Gem cutters must orient the stone carefully during cutting to display the most desirable blue-violet hue from the top.
- Mohs Hardness: 6 to 7. While harder than Turquoise, Tanzanite is still considered delicate for everyday jewelry, especially in rings or bracelets, due to its perfect cleavage in one direction, making it vulnerable to breakage from a sharp blow.
- Origin: Tanzanite's origin is incredibly specific. It is found in only one location in the world: the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. This extreme rarity is a primary factor in its high value.
Zircon
Zircon is a silicate mineral (zirconium silicate, ZrSiO₄) and is one of the hardest natural gemstones, not to be confused with cubic zirconia (CZ), a lab-created diamond simulant). Blue zircon is most often created by heating brownish zircon crystals—a common practice in the gem trade—to remove the brown color and produce a stable blue. This heat treatment is permanent and widely accepted.
- Mohs Hardness: 6.5 to 7.5. Zircon is reasonably durable, though its perfect cleavage in two directions makes it susceptible to chipping if struck with force. It is suitable for most jewelry types with proper care.
- Major Origins: While sources are not detailed extensively in the provided materials, blue topaz, often grouped with zircon, is mined in Sri Lanka, Brazil, Mexico, Nigeria, and the U.S. The sources note that zircon is a traditional birthstone for December.
Summary of Gemological Properties
| Gemstone | Mineral Group | Chemical Composition | Mohs Hardness | Key Characteristics |
|---|---|---|---|---|
| Turquoise | Phosphate | Hydrated copper/aluminum phosphate | 5 - 6 | Opaque, often with a dark matrix |
| Tanzanite | Zoisite (Silicate) | Calcium aluminum silicate with Vanadium | 6 - 7 | Transparent, strongly pleochroic |
| Zircon | Zirconium Silicate | ZrSiO₄ | 6.5 - 7.5 | Transparent, brilliant fire, perfect cleavage |
Symbolism and Metaphysical Lore
Across cultures and centuries, gemstones have been imbued with meaning and metaphysical properties. The December birthstones are no exception, each carrying a unique set of beliefs.
Turquoise is perhaps the most storied of the three in terms of protective lore. It has long been regarded as a talisman against harm and ill will. Many cultures believed it could change color to warn its owner of impending danger or illness. It is also strongly associated with friendship and good fortune, making it a popular gift to convey goodwill and affection. Its calming blue-green color is thought to promote tranquility and inner peace.
Tanzanite, as a modern gem, has developed a more contemporary symbolism focused on personal growth and consciousness. It is often associated with transformation, encouraging individuals to embrace change and embark on new beginnings. Its unique color and rarity are said to inspire a sense of individuality and higher purpose. Some believe it can facilitate a connection between the heart and mind, promoting a balanced and clear perspective.
Zircon is linked to clarity of thought, wisdom, and spiritual grounding. Its brilliant sparkle is believed to help focus the mind and aid in concentration. It is also associated with a sense of balance and honor. In some traditions, Zircon is thought to promote prosperity and honor, making it a stone of success.
These metaphysical attributes, while not scientifically proven, add a rich layer of cultural significance to these gems, enhancing their appeal for those seeking a deeper connection to their birthstone.
Selecting, Wearing, and Caring for Your Gem
The durability of a gemstone dictates how it can be worn and how it should be cared for. Given their varying hardness and cleavage characteristics, the December birthstones require different levels of attention.
Turquoise Care
Due to its porosity and relatively low hardness, Turquoise requires careful handling. * Avoid Chemicals: Keep it away from cosmetics, perfumes, lotions, and household cleaners, which can discolor or damage the stone. * Gentle Cleaning: Clean with a soft, dry cloth. If necessary, use lukewarm water with a drop of mild soap, but dry it immediately and thoroughly. Ultrasonic and steam cleaners are not safe. * Storage: Store it separately from other jewelry to prevent scratching. Keep it away from excessive heat or direct sunlight, which can cause fading.
Tanzanite Care
Tanzanite's beauty is matched by its delicacy. * Protect from Impact: Due to its perfect cleavage, avoid wearing Tanzanite in rings or bracelets during activities where it might be knocked. It is best suited for earrings and pendants. * Temperature Shocks: Avoid exposing Tanzanite to sudden, extreme temperature changes. * Gentle Cleaning: Use warm water, a drop of mild soap, and a soft brush. Ultrasonic and steam cleaners are not recommended.
Zircon Care
Zircon is durable but has cleavage, so it needs protection from hard knocks. * Prevent Chipping: Be mindful of the stone's edges, which can chip if struck. It is generally safe for most jewelry types but benefits from protective settings. * Cleaning: Use warm soapy water and a soft brush. Avoid ultrasonic cleaners, as the vibrations can cause existing tiny fractures to worsen. Most heat-treated blue zircon is stable in light, but it's best to avoid prolonged exposure to intense heat.
For those considering Blue Topaz, which is often included in the modern list of December stones, it is noted for its high durability. With a Mohs hardness of 8, it is the hardest of the December options, making it an excellent choice for everyday wear. However, like Zircon, it has deep cleavage, meaning it can still be chipped by a sharp impact.
Conclusion
The birthstones of December—Turquoise, Tanzanite, and Zircon—offer a remarkable diversity that reflects the richness of the month itself. From the ancient, protective talisman of Turquoise, with its earthy matrix and storied past, to the vibrant, transformative energy of the modern marvel Tanzanite, and the brilliant, wise sparkle of ancient Zircon, each gem presents a unique narrative. Their differences in hardness, origin, and appearance provide a perfect range of choices for any preference or lifestyle. Whether chosen for its historical significance, geological rarity, or symbolic meaning, a December birthstone is a vibrant piece of the natural world, a celebration of a winter month marked by clarity, brilliance, and enduring beauty.