The month of December is uniquely associated with a quartet of gemstones, each offering a distinct shade of blue that evokes the cool, serene palette of winter. While many months claim a single birthstone, December boasts a diverse collection: turquoise, zircon, tanzanite, and blue topaz. This variety provides individuals born in December with ample choice, allowing them to select a stone that resonates with their personal style, budget, and the symbolic meanings they hold dear. The common thread among these gems is their captivating blue hue, ranging from the soft, sky-like tones of turquoise to the deep, velvety blues of tanzanite and the brilliant, clear blues of zircon and topaz. This article delves into the rich history, geological origins, gemological properties, and cultural significance of each of December’s birthstones, providing a thorough resource for gemstone enthusiasts, jewelry buyers, and students of gemology.
History and Lore
The historical narratives of December’s birthstones are as varied as their colors, spanning millennia and crossing continents. Each stone carries a legacy of human fascination and belief.
Turquoise stands as one of the oldest known gemstones, cherished for millennia. Its use dates back to ancient Egypt, where pharaohs and other rulers adorned themselves with this vibrant stone. Chinese artisans were carving turquoise more than 3,000 years ago, demonstrating its early significance in Eastern cultures. Across the Atlantic, turquoise played a pivotal role in the lives of Native American peoples; the Apache believed it could be found by following a rainbow to its end. Historically, turquoise was attributed with numerous protective powers. From the 13th century onward, it was believed to safeguard the wearer from falls, particularly from horses, and was thought to shatter into pieces as a warning of impending disaster. Hindu mystics maintained that beholding a turquoise after seeing the new moon would ensure fantastic wealth. This long-standing association with protection and good fortune has cemented turquoise’s status as a talismanic stone throughout history.
Zircon boasts an equally ancient lineage, though its name and identity have been subjects of colorful debate. The word “zircon” may derive from the Arabic zarkun (meaning “cinnabar” or “vermilion”) or the Persian zargun (“gold colored”), both fitting given the stone’s broad color palette, which includes red, orange, yellow, brown, green, and blue. For centuries, colorless zircon, prized for its brilliance and flashes of multicolored light known as fire, was often confused with diamond. This confusion was particularly prevalent during the Middle Ages, when zircon was believed to induce deep sleep and ward off evil spirits. In the Hindu religion, zircon is one of the nine gems in the navaratna; when worn together, these gems are said to protect the wearer and bring wealth, wisdom, and good health. By the Victorian era, blue zircon had gained particular favor.
Tanzanite is a distinctly modern addition to the gemological world. Unlike the ancient stones, its discovery is well-documented in recent history. It was first identified in the Merelani Hills of Tanzania in the late 1960s, though some sources specify the exact year as 1967. Its rapid rise to prominence is notable; Tiffany & Co. recognized its potential and introduced it to the global market in 1968, naming it after its country of origin. This strategic move helped establish tanzanite as a celebrated blue gemstone within a few short years.
Blue Topaz is not a traditional December birthstone but has been added to the list in modern times, quickly gaining popularity for its crisp winter blue color and exceptional durability. Its inclusion reflects a trend toward offering consumers more flexibility in terms of price, durability, and style. While its historical lore is less prominent than that of turquoise or zircon, its modern appeal lies in its accessibility and robust physical properties.
Geological Formation and Sources
Understanding where these gemstones are formed and mined provides insight into their rarity and value.
Turquoise is a hydrous phosphate of copper and aluminum, forming in arid regions where acidic, copper-rich groundwater interacts with aluminum-bearing minerals. The color, ranging from sky blue to greenish-blue, is primarily determined by the amount of copper (blue) or iron (green) present. Major sources include Iran (historically the source of the finest "Persian turquoise"), the United States (notably Arizona and Nevada), Tibet, and India. The presence of matrix—the host rock in which the turquoise formed—is common and can create distinctive veined patterns.
Zircon is a zirconium silicate (ZrSiO₄) and is one of the oldest minerals on Earth, with some crystals dating back billions of years. It forms in igneous and metamorphic rocks. While it occurs in many colors, the vibrant blues favored in jewelry are often the result of heat treatment of brownish zircon. Primary sources for gem-quality zircon include Australia, Cambodia, Sri Lanka, and Thailand.
Tanzanite is a variety of the mineral zoisite, colored by vanadium. It is found in only one location in the world: the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. This extremely limited geographic source contributes to its value and rarity. The stones are typically found in elongated, tabular crystals within a host rock of calcite and graphite.
Blue Topaz is a silicate mineral with the chemical formula Al₂SiO₄(F,OH)₂. Natural blue topaz is rare; most of the vivid blue topaz available in the market is the result of irradiation and heat treatment of colorless or pale blue topaz. Major sources of topaz include Brazil, Sri Lanka, Nigeria, and the United States (particularly Texas).
Gemological Properties
The physical and optical properties of a gemstone determine its durability, brilliance, and suitability for different types of jewelry. The following table summarizes key properties for each December birthstone, based on data from gemological sources.
| Gemstone | Chemical Composition | Mohs Hardness | Typical Colors | Common Treatments | Notable Optical Features |
|---|---|---|---|---|---|
| Turquoise | Hydrous copper aluminum phosphate | 5 – 6 | Sky blue to greenish-blue | Stabilization (impregnation with resin/wax) | Opaque to semi-translucent; often contains matrix (veins of host rock). |
| Zircon | Zirconium silicate (ZrSiO₄) | 6.5 – 7.5 | Blue (often from heat treatment of brown), also colorless, yellow, brown, red | Heat treatment (for blue color), irradiation | High refractive index and strong dispersion ("fire"), especially in colorless varieties. |
| Tanzanite | Calcium aluminum hydroxyl sorosilicate (Zoisiite variety) | 6 – 7 | Violet-blue to deep blue, often pleochroic | Heat treatment (to enhance blue color) | Strong pleochroism (shows different colors from different angles: blue, violet, burgundy). |
| Blue Topaz | Aluminum silicate with fluorine/hydroxyl | 8 | Sky Blue, Swiss Blue, London Blue (all from treatment) | Irradiation and heat treatment | Typically transparent with good brilliance; color is stable and permanent. |
Turquoise has a relatively low hardness (5-6 on the Mohs scale), making it susceptible to scratching and damage. It is also porous, which is why it is often stabilized with resins or waxes to enhance durability and color uniformity. Its opacity and characteristic matrix patterns are key identifiers.
Zircon is significantly harder (6.5-7.5), making it more suitable for a variety of jewelry settings, including rings. Its high refractive index gives it exceptional brilliance, and its strong dispersion contributes to a fiery sparkle that can rival diamond. Blue zircon, while popular, can be brittle and prone to chipping due to its crystal structure.
Tanzanite has a hardness of 6-7, placing it in the moderate range. It is pleochroic, meaning it exhibits different colors when viewed from different crystal directions. The most desirable color is a deep, saturated blue-violet, which is typically achieved through a controlled heat treatment of the naturally brownish material. This treatment is standard and permanent. Due to its relative softness and cleavage (a tendency to split along internal planes), tanzanite is best set in protective mountings for earrings or pendants rather than rings for daily wear.
Blue Topaz is the hardest of the group (8 on the Mohs scale), making it exceptionally durable and resistant to scratching and abrasion. This property, combined with its vibrant, consistent blue color, makes it an excellent choice for rings and other jewelry intended for everyday wear. The blue color in topaz is almost always the result of treatment, but this process is stable and does not affect the stone's durability.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, December’s birthstones are imbued with rich symbolic meanings and metaphysical properties, which have evolved over centuries.
Turquoise is widely regarded as a stone of protection, healing, and friendship. It is considered a steadying force, offering grounding and a sense of calm during chaotic times. Its traditional significance includes good fortune and health, and it is often worn as a talisman against negative energies and physical harm.
Tanzanite, a stone of modern discovery, is associated with transformation, intuition, and spiritual growth. Its blue-violet hue is said to reflect the energy of new beginnings and clarity of mind. It is believed to facilitate a connection between the heart and mind, encouraging the wearer to embrace change and step into new chapters of life with curiosity and purpose.
Zircon is linked to wisdom, prosperity, and good fortune. It is believed to sharpen focus, boost mental clarity, and enhance a sense of balance. In various cultural traditions, it has been used to promote spiritual protection and attract wealth.
Blue Topaz symbolizes clarity, communication, and calmness. Its cool blue tone is associated with serene energy, making it a popular choice for those seeking to reduce stress and improve honest self-expression. It is often considered a stone of peaceful communication.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of any gemstone jewelry. The varying hardness and stability of December’s birthstones necessitate specific handling guidelines.
Turquoise: Due to its porosity and relatively low hardness, turquoise requires gentle care. Avoid exposing it to chemicals, including perfumes, lotions, and household cleaners, which can damage its surface. Clean it with a soft, damp cloth and mild soap. Ultrasonic and steam cleaners should never be used, as they can cause cracking or discoloration. Store it separately from harder gemstones to prevent scratching.
Zircon: While harder than turquoise, zircon can be brittle. It is advisable to avoid sudden temperature changes and harsh impacts. Clean it with warm soapy water and a soft brush. Avoid ultrasonic cleaners, especially for stones that may have inclusions, and be cautious with steam cleaners.
Tanzanite: This stone is best set in earrings or pendants rather than rings for daily wear due to its moderate hardness and cleavage. If worn in a ring, a protective setting is recommended. Clean tanzanite with warm, soapy water and a soft brush. Ultrasonic and steam cleaners are never recommended, as they can cause damage.
Blue Topaz: As the hardest of the group, blue topaz is relatively easy to care for. It can be cleaned with warm soapy water and a soft brush. Ultrasonic cleaners are generally safe, but steam cleaning should be approached with caution due to potential thermal shock, though it is less risky for topaz than for softer stones. Its durability makes it suitable for everyday wear, but it should still be stored carefully to avoid scratching other gems.
Conclusion
December’s birthstones offer a remarkable spectrum of blue gemstones, each with a unique story, set of properties, and cultural significance. From the ancient protective talisman of turquoise and the fiery brilliance of zircon to the modern transformative allure of tanzanite and the durable, vibrant blue of topaz, these gems provide a wealth of choices for those born in the final month of the year. Understanding their histories, geological origins, gemological characteristics, and care requirements allows for an informed and meaningful selection, whether for personal adornment, a gift, or academic study. Together, they capture the serene and profound beauty of winter, making them enduring symbols of December’s distinctive character.