Turquoise, Blue Topaz, and the Panoply of December Birthstones

The month of December is uniquely associated with a quartet of captivating blue gemstones: Turquoise, Blue Topaz, Tanzanite, and Blue Zircon. This abundance of choice is unlike any other month, offering those born in the winter season a diverse palette of colors and properties to match their personal style and preference. While each stone possesses its own distinct geological origin, historical narrative, and symbolic meaning, they are united by their cool, wintry hues that evoke the clarity of a winter sky and the depth of frozen waters. The selection of these stones is not merely a matter of aesthetics; it reflects a rich tapestry of geological discovery, commercial adaptation, and evolving cultural beliefs. Understanding the unique characteristics of each stone—from the ancient, earthy allure of Turquoise to the modern, brilliant durability of Blue Topaz—provides insight into why they have secured their place as cherished birthstones for December.

The modern list of December birthstones is a product of both tradition and evolution. The standardization of birthstones began in 1912 with the National Association of Jewelers, which combined historical customs with gemstones deemed practical for the jewelry trade. The list has since been updated to include new discoveries and commercial offerings. In 1952, the Jewelry Industry Council of America added Blue Zircon to December’s list, and in 2002, the American Gem Trade Association added the recently discovered Tanzanite. Turquoise remains the traditional birthstone, valued for its ancient history, while Blue Topaz has become a popular modern choice, particularly in the United States market. This evolution underscores how birthstone lists can adapt to reflect new gemstone discoveries and commercial availability, ensuring that the options remain relevant and appealing to contemporary consumers.

History and Lore: From Ancient Amulets to Modern Lists

The history of these December birthstones spans millennia, with Turquoise being the most ancient of the group. While the precise origins of its use are deeply rooted in antiquity, Turquoise has been a prized gemstone in many cultures, particularly in Persia (modern-day Iran) and among the indigenous peoples of the American Southwest. Its name is derived from the French pierre turquoise, meaning "Turkish stone," as it was originally brought to Europe through Turkish trade routes. However, the most highly prized turquoise has historically come from Persia, the United States (Arizona, New Mexico, Nevada), and Mongolia. The stone’s color, ranging from sky blue to greenish hues, was believed to be influenced by its geographical origin, with copper deposits yielding the coveted blue tones and iron resulting in greener shades.

Turquoise has long been associated with protection, friendship, and healing. It was worn as an amulet to ward off evil and was believed to change color to warn its wearer of impending danger or illness. This protective symbolism has made it a staple in jewelry for centuries, often set in silver and worn by warriors and travelers. Its significance is deeply embedded in the cultural heritage of many civilizations, serving not just as adornment but as a spiritual and talismanic object.

In contrast, the histories of Blue Topaz, Tanzanite, and Blue Zircon are more recent or have been shaped by modern gemology. The name "Topaz" itself has a complex origin. It is often said to derive from the Greek word Topazios, the ancient name of an island in the Red Sea. However, it was later discovered that the stones mined on this island were actually Peridot, not Topaz. Another theory suggests the name comes from the Sanskrit word for "fire." The natural blue variety of topaz was historically rare, and for much of history, the term "topaz" was used to describe any yellow gemstone. The vibrant blue topaz we know today is largely a product of modern gemological treatments. Most commercially available blue topaz is created by irradiating naturally colorless topaz, a process that stabilizes the color and enhances its brilliance. This technological advancement made blue topaz widely available and affordable, leading to its rapid rise in popularity as a modern birthstone.

Tanzanite’s history is remarkably short but dramatic. Discovered in the late 1960s in the Merelani Hills of Tanzania, this gemstone was quickly recognized for its extraordinary violet-blue hue and pleochroism—the property of showing different colors (like blue, violet, and burgundy) from different viewing angles. Its addition to the official birthstone list in 2002 marked one of the most significant updates to the modern list, reflecting the influence of a single, unique geological source and a powerful marketing campaign by Tiffany & Co.

Blue Zircon’s inclusion in the 1952 update also speaks to its renewed appeal. Zircon is one of the oldest minerals on Earth, with crystals dating back billions of years. However, its use as a gemstone was often overshadowed by its confusion with the synthetic material cubic zirconia. Despite this, natural zircon possesses exceptional brilliance and fire, rivaling that of diamonds due to its high refractive index. Its journey onto the birthstone list represents a reclamation of its status as a valuable natural gemstone.

Geological Formation and Sources

Each of the December birthstones forms under distinct geological conditions, which directly influences their availability and characteristics.

Turquoise is a hydrated phosphate of aluminum and copper, with the chemical formula Al₂(OH)PO₄·4H₂O. It forms in arid regions within the oxidized zones of copper deposits. This environment is crucial for the deposition of the minerals that create turquoise. As groundwater percolates through copper-rich rocks, it dissolves the minerals and, in the presence of phosphorus and aluminum, precipitates turquoise in veins and nodules. Its formation is often irregular, leading to a porous structure. The most significant sources of turquoise are in Persia (Iran), the United States (particularly Arizona, New Mexico, and Nevada), and Mongolia. The color is directly tied to its chemical composition; copper imparts the classic blue color, while iron can result in greenish hues.

Blue Topaz is a silicate mineral with the chemical formula Al₂SiO₆. It crystallizes in igneous and metamorphic rocks, often in large, well-formed crystals. Unlike turquoise, its natural blue color is exceedingly rare. The vast majority of blue topaz on the market begins as colorless or pale topaz, which is then subjected to irradiation and heat treatment to achieve the desired blue hue. This process is stable and permanent, making the treated stones durable for jewelry. Major sources for the raw material include Brazil, Nigeria, and the United States, with Sri Lanka and Mexico also mentioned as sources for blue topaz.

Tanzanite is a variety of the mineral zoisite, with the chemical formula Ca₂Al₃(SiO₄)₃(OH). It is a relatively recent geological discovery, formed by the intense heat and pressure of tectonic activity in the East African Rift Valley. This specific geological event created the conditions for tanzanite to form, and its occurrence is incredibly limited. To date, tanzanite has only been found in a single, small mining area in the Merelani Hills of Northern Tanzania, near the base of Mount Kilimanjaro. This extreme rarity is a primary factor in its high value and cost.

Blue Zircon is a zirconium silicate (ZrSiO₄), one of the oldest minerals known to science. It forms in igneous rocks, particularly in granites and pegmatites. Zircon crystals are extremely durable and resistant to weathering, which is why they are often found in sedimentary deposits as well. While zircon occurs in many colors, the blue variety is typically the result of heat treatment of brown zircon crystals. Major sources for gem-quality zircon include Australia, Cambodia, Sri Lanka, and Thailand.

Gemological Properties and Durability

Understanding the physical and optical properties of these gemstones is essential for both jewelers and consumers, as it dictates their suitability for different types of jewelry and their care requirements.

The following table summarizes the key gemological properties of the four December birthstones, based on the provided sources:

Gemstone	Chemical Composition	Mohs Hardness	Key Properties & Notes
Turquoise	Al₂(OH)PO₄·4H₂O	5 - 6	Relatively soft and porous; sensitive to heat, chemicals, and oils.
Blue Topaz	Al₂SiO₆	8	Hardest December birthstone; durable for everyday wear.
Tanzanite	Ca₂Al₃(SiO₄)₃(OH)	6 - 7	Shows pleochroism (multiple colors); requires protective settings.
Blue Zircon	ZrSiO₄	6.5 - 7.5	High refractive index (brilliant); can be brittle; heat-treated for color.

Turquoise has a hardness of 5 to 6 on the Mohs scale, making it one of the softer gemstones used in jewelry. Its porosity is a significant factor; it can absorb oils, chemicals, and even sweat, which can alter its color over time. This sensitivity means it is not ideal for rings or bracelets that receive daily wear and tear. Instead, it is often used in pendants, earrings, and other pieces that are less exposed to impact and harsh conditions.

Blue Topaz is notably the hardest and most durable of the December birthstones, with a Mohs hardness of 8. This makes it an excellent choice for all types of jewelry, including rings and bracelets intended for daily wear. Its glass-like luster and deep cleavage (a tendency to break along flat planes) are important considerations for cutters, but its overall toughness and resistance to scratching are superior among the group.

Tanzanite has a hardness of 6 to 7 on the Mohs scale. While harder than turquoise, it is still considered relatively delicate for a gemstone. Its most famous characteristic is pleochroism, where a single stone can display a range of colors from blue to violet to reddish-brown depending on the crystal orientation. This property requires skilled cutting to maximize the desired blue-violet hue. Due to its brittleness and the need to protect its color, tanzanite is often set in protective settings like bezels.

Blue Zircon has a hardness of 6.5 to 7.5, placing it in the moderate range. It is prized for its exceptional brilliance and fire, which can rival that of diamonds. This is due to its high refractive index. However, zircon can be brittle and prone to chipping, so it requires careful handling and setting, especially in pieces like rings that are subject to impact. The blue color in gem-quality zircon is almost always the result of heat treatment, which transforms brown zircon into a stable blue.

Symbolism and Metaphysical Beliefs

Beyond their physical beauty, each December birthstone carries a legacy of symbolic meaning and metaphysical belief, which has evolved over centuries.

Turquoise is perhaps the most symbolically charged stone of the group. Across cultures, it has been revered as a stone of protection, luck, and healing. It is believed to be a conduit for spiritual grounding, offering calm and stability to its wearer. In many traditions, turquoise is thought to promote friendship and peace, making it a meaningful gift. Its association with the sky and water in various mythologies links it to concepts of purity and life-giving force.

Blue Topaz is associated with clarity, communication, and calmness. It is often called the "stone of communication," believed to help express thoughts and feelings clearly and confidently. Metaphysically, it is linked to emotional healing, encouraging patience, relaxation, and a positive mindset. Its soothing blue color is said to have a calming effect on the mind and emotions.

Tanzanite, with its recent discovery, has quickly accumulated symbolic meanings tied to its unique appearance and origin. It is often associated with transformation, intuition, and spiritual growth. Its pleochroic nature, showing different colors from different angles, is seen as a metaphor for seeing the world from new perspectives and embracing change. It is considered a stone of higher consciousness and intuition.

Blue Zircon is traditionally associated with wisdom, prosperity, and honor. Its brilliant sparkle has linked it to concepts of light and clarity, and it is believed to bring peace and honor to its wearer. Some traditions also associate it with cleansing the spirit and promoting positive energy. Its historical use as a protective stone further reinforces its symbolic role as a bearer of good fortune.

Care and Cleaning

Proper care is essential to maintain the beauty and longevity of any gemstone, and the December birthstones have specific requirements due to their varying properties.

Turquoise requires the most careful handling. Due to its softness and porosity, it should be protected from scratches, chemicals, and extreme heat. Clean turquoise jewelry with a soft, dry cloth. Avoid ultrasonic cleaners, steam cleaners, and any household chemicals, including soaps and lotions, which can penetrate the stone and cause discoloration or damage. Store turquoise separately from harder gems to prevent scratching.

Blue Topaz, with its high hardness of 8, is relatively easy to care for. It can be cleaned with warm water, mild soap, and a soft brush. While it is durable, it is still important to protect it from hard blows and extreme temperature changes, as the cleavage planes can be a point of weakness. Ultrasonic cleaners are generally safe for blue topaz, but steam cleaning should be avoided if the stone has been treated or if there are any fractures.

Tanzanite is more delicate and should be handled with care. It is recommended to clean tanzanite jewelry with a soft brush, warm water, and a mild detergent. Avoid ultrasonic and steam cleaners, as the vibrations and heat can cause damage, especially if the stone has inclusions or fractures. Given its brittleness, protective settings are advised, and it should be stored carefully to avoid impact.

Blue Zircon is moderately hard but can be brittle. It is best cleaned with a soft brush, warm water, and mild soap. Avoid ultrasonic cleaners and sudden temperature changes, as these can cause the stone to fracture. Due to its brittleness, zircon should be stored separately to prevent scratching or chipping from contact with other jewelry pieces.

Conclusion

The December birthstones—Turquoise, Blue Topaz, Tanzanite, and Blue Zircon—offer a remarkable spectrum of blue gemstones, each with a unique story, geological origin, and set of properties. From the ancient, protective talisman of Turquoise to the modern, durable brilliance of Blue Topaz, and the rare, transformative allure of Tanzanite to the timeless, fiery sparkle of Blue Zircon, these stones provide a wealth of choice for those born in the winter month. Their inclusion on the official birthstone list is a testament to both historical tradition and the dynamic nature of gemology, where new discoveries and commercial developments continually shape our understanding and appreciation of precious stones. By understanding their histories, properties, and care requirements, enthusiasts and collectors can make informed choices and cherish these beautiful blue gems for a lifetime.