The month of December is uniquely distinguished in the world of gemology by its association with not one, but four distinct birthstones. This multiplicity offers a remarkable spectrum of color and character, from the opaque, earthy tones of turquoise to the brilliant, fiery sparkle of zircon. Unlike months with a single traditional gem, December’s selection—traditionally turquoise and zircon, with tanzanite and blue topaz joining the modern list—provides a diverse palette of blue and green hues that perfectly mirror the cool, reflective light of winter. This article delves into the history, geology, gemological properties, and cultural significance of these four celebrated gems: Turquoise, Tanzanite, Blue Topaz, and Zircon. Each stone carries its own story, from ancient civilizations to modern jewelry design, and understanding their unique attributes is essential for collectors, enthusiasts, and anyone seeking a meaningful piece of December birthstone jewelry.
History and Lore
The historical tapestry of December’s birthstones is rich and varied, with each gem carrying centuries of cultural weight and symbolic meaning.
Turquoise stands as one of the oldest known gemstones, cherished for millennia. Its use dates back over 3,000 years, with Chinese artisans carving it during ancient times. The pharaohs and rulers of ancient Egypt adorned themselves with this semi-translucent to opaque blue-green stone, believing it possessed protective and healing powers. Hindu mystics held a belief that seeing turquoise after beholding the new moon would ensure fantastic wealth. A recurring theme in its lore is protection; from the 13th century onward, it was thought to safeguard the wearer from falls, particularly from horses, and was believed to break into pieces as a warning of impending disaster. For Native American cultures, particularly the Apache, turquoise held a spiritual significance, with legends suggesting it could be found by following a rainbow to its end. This deep-rooted history establishes turquoise not merely as a decorative stone but as an object of profound spiritual and protective significance across continents and eras.
Tanzanite is a relative newcomer to the gemological world, lacking the ancient lore of its December counterparts. Its story begins in the 20th century, with its discovery in Tanzania, East Africa. While it does not have millennia of history behind it, tanzanite has quickly been imbued with modern symbolism. It is associated with transformation, intuition, and spiritual growth. Its rapid rise to prominence as a December birthstone is a testament to its captivating beauty and unique color, which has made it a favorite for contemporary jewelry design.
Blue Topaz, while topaz itself is an ancient stone, the blue variety’s association with December is modern. The word "topaz" is believed to derive from the Sanskrit "tapas," meaning fire. Historically, topaz was linked to strength and protection. However, naturally occurring blue topaz is rare; most of the vibrant blue stones on the market today are the result of heat-treating colorless topaz. In modern times, blue topaz has become synonymous with clarity, love, and fidelity. It is a popular choice for romantic gifts, symbolizing calmness and clear communication. Its journey from a naturally rare gem to a widely available, treated beauty has made it a mainstream and accessible option for December birthdays.
Zircon is one of the oldest known gemstones on Earth, with some specimens dating back billions of years. Despite its age, its association with December is more traditional than ancient. Zircon is linked to wisdom, prosperity, and good fortune. It is often confused with the synthetic cubic zirconia, a distinction that frustrates gemologists but underscores the stone’s brilliance. Zircon’s history is tied to its fiery sparkle, which was highly prized in earlier centuries before the advent of modern diamond alternatives.
The modern list of December birthstones was formalized to offer variety. The Gemological Institute of America (GIA) officially recognizes Turquoise, Tanzanite, and Zircon. Blue Topaz, while not part of the traditional trio, has gained such immense popularity that it is now frequently treated as a mainstream December birthstone, offering consumers greater flexibility in price, durability, and style.
Geological Formation and Sources
The origins of these four gems are as diverse as their colors, spanning the globe from the arid landscapes of the American Southwest to the volcanic soils of East Africa.
Turquoise is a hydrous phosphate of copper and aluminum. It is not formed in igneous or metamorphic rocks like many gems but is a secondary mineral that forms in the near-surface environment where acidic, copper-rich waters percolate through pre-existing rocks containing aluminum and phosphorus. This process can take millions of years. The gem is found worldwide, with significant deposits in the United States (particularly in Arizona, New Mexico, and Nevada), Iran, China, and Egypt. The stone is often found with a matrix—veins of the host rock (like limonite or sandstone) embedded within it, which contributes to its distinctive, web-like patterns.
Tanzanite has an exclusive geographical origin. It is found in only one place on Earth: a small, four-square-kilometer mining area in the Merelani Hills of Northern Tanzania, near Mount Kilimanjaro. This unique locality makes tanzanite significantly rarer than diamond. The gem is a variety of the mineral zoisite and is formed by the intense heat and pressure that acted upon the host rock during the formation of the East African Rift Valley. The heat from this geological event recrystallized the zoisite, introducing vanadium, which gives tanzanite its signature blue-violet color.
Blue Topaz is a variety of the topaz mineral, which is a silicate of fluorine and aluminum. Topaz crystallizes in pegmatites and gas cavities in igneous rocks like rhyolite. While topaz is found in many locations globally—including Brazil, Sri Lanka, and Nigeria—naturally occurring blue topaz is exceptionally rare. The vast majority of blue topaz in the market is created by irradiating and then heating colorless topaz. This treatment process is stable and permanent, resulting in the consistent and vibrant blue hues (such as Sky Blue, Swiss Blue, and London Blue) that consumers desire. The United States, particularly Texas (where it is the state gem), Utah, and California, has sources for blue topaz, though commercial quantities for jewelry are limited.
Zircon is a zirconium silicate and is one of the oldest minerals on Earth. It forms in igneous and metamorphic rocks, often found in heavy mineral sands derived from the erosion of granites. Major sources include Sri Lanka, Cambodia, Australia, and Norway. Zircon crystals are prized for their high refractive index and strong dispersion, which gives them a brilliant fire. While often found in a range of colors, the bright, clear blue varieties are most sought after for jewelry.
Gemological Properties
Understanding the physical and optical properties of these gems is crucial for identification, valuation, and proper care. The following table summarizes key gemological data for the four December birthstones, based on the provided information.
| Gemstone | Color & Varieties | Mohs Hardness | Chemical Composition (from sources) | Typical Clarity & Appearance |
|---|---|---|---|---|
| Turquoise | Blue to green, often opaque with matrix veins | 5 – 6 | Hydrous phosphate of copper and aluminum (implied) | Semi-translucent to opaque; often contains host rock matrix |
| Tanzanite | Violet-blue to deep blue, pleochroic | 6 – 7 | A variety of zoisite (implied) | Can be transparent to translucent; exhibits strong pleochroism (color change from different angles) |
| Blue Topaz | Sky Blue, Swiss Blue, London Blue | 8 | Silicate of fluorine and aluminum (implied) | Typically transparent and clear; treated to achieve blue color |
| Zircon | Brilliant blue (also multi-color) | 6.5 – 7.5 | Zirconium silicate | High brilliance and fire; can be transparent or opaque depending on type |
Turquoise is the softest of the four, with a Mohs hardness of 5 to 6. Its porosity and sensitivity to chemicals and moisture require careful handling. The presence of matrix (veins of host rock) is a natural characteristic and not a flaw, though it affects the stone’s durability and cleaning needs.
Tanzanite has a hardness of 6 to 7, making it suitable for jewelry but requiring protection from sharp blows. Its most distinctive property is pleochroism—the ability to display different colors (blue, violet, and burgundy) when viewed from different crystal directions. This is a key identifying feature. It is also commonly heat-treated to enhance its blue color, a stable and widely accepted practice.
Blue Topaz is notably hard, with a Mohs hardness of 8. This makes it one of the most durable gemstones for daily wear, suitable for rings and other pieces subject to impact. Its clarity is typically excellent, and its color is almost always the result of treatment, which is stable and does not fade.
Zircon has a hardness of 6.5 to 7.5, placing it in a moderate range. It is known for its exceptional brilliance and fire, which can rival that of diamond. However, zircon is brittle and can be prone to chipping along its edges, especially in faceted cuts. It is also sensitive to heat and pressure, and ultrasonic or steam cleaning is not recommended.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, each December gemstone carries a universe of symbolic meaning and metaphysical belief, offering wearers a connection to specific intentions and energies.
Turquoise is universally regarded as a stone of protection, healing, and friendship. Its historical use as a talisman against falls and disaster underscores its role as a guardian stone. In modern metaphysical circles, it is believed to promote emotional balance, soothe anxiety, and foster honest communication. Its connection to the sky and water elements makes it a symbol of peace and tranquility, aligning with its calming blue-green hues.
Tanzanite is embraced for its connection to transformation, intuition, and spiritual growth. As a relatively new stone, its symbolism is often tied to its origin story—formed by the immense geological forces of the East African Rift. It is thought to facilitate a connection between the heart and the mind, encouraging the wearer to embrace change and pursue a higher spiritual path. Its shifting colors are seen as a metaphor for the multifaceted nature of the soul.
Blue Topaz symbolizes clarity, communication, and calmness. Its cool blue tones are associated with clear thinking and truthful expression, making it a popular stone for public speakers, writers, and those in need of mental focus. In romantic contexts, it represents love and fidelity, serving as a modern emblem of commitment. Its hardness and clarity reflect the stone’s symbolic properties of resilience and transparency.
Zircon is linked to wisdom, prosperity, and good fortune. Its fiery brilliance is believed to attract wealth and success, while its ancient origins connect it to the wisdom of the earth. Zircon is also thought to promote self-confidence and a sense of balance. In some traditions, it is used to aid in restful sleep and to ward off nightmares, adding a layer of protective symbolism.
Care and Cleaning
Proper maintenance is essential to preserve the beauty and longevity of any gemstone. The varying physical properties of December’s birthstones necessitate distinct care routines.
Turquoise, with its porosity and relative softness (5-6 Mohs), requires the most gentle handling. It is sensitive to chemicals, including those found in cosmetics, lotions, and even some soaps. The best cleaning method is using warm, soapy water and a soft brush, followed by immediate thorough drying. It should be stored separately to avoid scratches from harder materials. Avoid ultrasonic cleaners, steam, and prolonged exposure to water or heat, which can damage the stone or any stabilizing treatments it may have undergone.
Tanzanite (6-7 Mohs) should be cleaned with only mild soap, warm water, and a soft brush. It is prone to chipping and cracking from sharp impacts due to its cleavage. Therefore, it is best suited for jewelry that is less likely to receive knocks, such as earrings and pendants, rather than daily-wear rings. Ultrasonic and steam cleaners are not recommended, as they can cause thermal shock or exacerbate existing fractures.
Blue Topaz (8 Mohs) is the most durable of the group and can withstand more rigorous cleaning. Warm, soapy water and a soft brush are safe. However, it is sensitive to sharp, hard impacts, which could cause chipping despite its high hardness. It is generally safe for daily wear in rings, but care should be taken to avoid subjecting it to severe blows. Ultrasonic cleaners are typically safe for untreated or heat-treated blue topaz, but caution is advised for stones with fractures or inclusions.
Zircon (6.5-7.5 Mohs) is brittle and should be handled with care to avoid chipping. Cleaning with warm, soapy water and a soft brush is best. Zircon is sensitive to heat and pressure, and steam and ultrasonic cleaners should be avoided entirely, as they can cause fractures or damage the stone. Due to its brittleness, it is often set in protective settings like bezels or halo rings, especially for pieces that will be worn regularly.
Conclusion
The four birthstones of December—Turquoise, Tanzanite, Blue Topaz, and Zircon—offer a remarkable diversity that caters to every taste and requirement. From the ancient, protective talisman of turquoise to the transformative, exclusive beauty of tanzanite; from the durable, communicative blue topaz to the brilliant, wise zircon, each gem provides a unique connection to the month of December. Their stories span from prehistoric times to the modern era, their origins span the globe, and their properties range from soft and porous to exceptionally hard and brilliant. This variety allows individuals to choose a stone that not only matches their aesthetic preferences but also resonates with their personal journey and symbolic intentions. Whether selected for its historical lore, geological uniqueness, metaphysical properties, or sheer durability for daily wear, a December birthstone is a timeless and meaningful choice, embodying the cool, clear, and multifaceted spirit of winter.