December is a unique month in the gemological calendar, distinguished by its affiliation with not one, but four distinct birthstones: Turquoise, Zircon, Tanzanite, and Blue Topaz. This multiplicity offers individuals born in the final month of the year a wide spectrum of choices regarding color, durability, and price. Unlike the singular gems associated with most other months, December’s options reflect a diverse history and geology, ranging from ancient talismans to modern discoveries.
The evolution of this list is a testament to the changing nature of the jewelry trade and the discovery of new deposits. While Turquoise and Zircon have long been recognized as traditional stones, the modern era introduced Tanzanite and the commercially popular Blue Topaz to the roster. This article explores the geological origins, gemological properties, historical lore, and care requirements of these four blue-hued stones, providing a definitive guide for collectors, enthusiasts, and prospective buyers.
History and Evolution of the December Birthstone List
The standardization of birthstones is a relatively modern practice, largely solidified in the early 20th century. The National Association of Jewelers (now known as the Jewelers of America) first formalized an official list in 1912. However, the list for December has seen significant updates, reflecting the industry's desire to provide variety and affordable options.
According to historical records, the initial recognized stones were Turquoise and Zircon. In 1952, the Jewelry Industry Council of America updated the list, adding Zircon (specifically blue zircon) to ensure a wider range of colors. The most recent major addition occurred in 2002, when Tanzanite was added to the list. This timeline highlights a pattern: as new gemstones are discovered and gain commercial traction, they are often considered for inclusion. Some sources suggest that the abundance of options for December was intended to provide more affordable choices for consumers, a theory supported by the varying price points of the four stones today.
Today, the Gemological Institute of America (GIA) recognizes Turquoise, Tanzanite, and Zircon as the primary December birthstones, while Blue Topaz is frequently cited as a fourth, mainstream option. This expansion offers consumers flexibility in price, durability, and style.
Turquoise: The Ancient Protector
Turquoise is perhaps the most historically significant of the December stones, cherished for millennia across various civilizations.
Geological Formation and Sources Turquoise is an opaque, semi-translucent gem that forms in arid regions where acidic waters percolate through rocks containing aluminum and copper. This process creates hydrous phosphate of copper and aluminum. The presence of copper results in the characteristic blue color, while iron imparts greenish hues. The gem often contains veins of "matrix"—remnants of the host rock in which it formed.
While historical sources of Turquoise are found in Egypt, China, and Persia, modern commercial mining occurs primarily in the Southwestern United States (Arizona, New Mexico, Nevada) and Iran. The "sleeping beauty" mine in Arizona is famous for producing pure sky-blue turquoise without matrix.
Gemological Properties Turquoise is relatively soft compared to other gemstones, with a Mohs hardness ranging from 5 to 6. This makes it susceptible to scratching and requires careful handling. It is typically cut en cabochon to highlight its color and matrix patterns.
History and Lore The name "Turquoise" likely derives from the French pierre tourques or "Turkish stone," referencing the historical trade routes that brought the stone from Persia to Europe through Turkey.
- Ancient Egypt: Pharaohs and rulers adorned themselves with Turquoise. It was found in the burial mask of Tutankhamun, highlighting its high status.
- China: Artifacts dating back over 3,000 years show Chinese artisans had mastered the carving of Turquoise.
- Native American Culture: The Apache believed Turquoise could be found by following a rainbow to its end. It has been a central element in the jewelry and spiritual life of many Southwestern tribes.
- Medieval Europe: It was believed to possess beneficial powers, guaranteeing health and good fortune. A specific superstition held that the stone would break into several pieces at the approach of disaster, warning the wearer of danger.
Symbolism Turquoise is universally associated with protection, healing, and friendship. It is often called the "stone of the sky," believed to bridge the earthly and spiritual worlds.
Care and Cleaning Due to its porosity and relative softness, Turquoise requires specific care. It is sensitive to heat, chemicals, and even the natural oils of the skin, which can cause discoloration over time. It should be cleaned only with warm, soapy water and a soft cloth. Avoid ultrasonic cleaners and steam cleaners.
Zircon: The Diamond Imitator
Zircon is one of the oldest minerals on Earth, yet it is often confused with synthetic cubic zirconia, a completely different material. Natural Zircon is a brilliant and valuable gem in its own right.
Geological Formation and Sources Zircon is a zirconium silicate that forms in igneous and metamorphic rocks. It is found in Australia, Sri Lanka, Thailand, and Cambodia. Australia is noted for having some of the oldest zircon crystals on the planet.
Gemological Properties Zircon is relatively hard, scoring between 6.5 and 7.5 on the Mohs scale, making it durable enough for most jewelry types. However, it can be brittle due to its crystal structure. Its most notable characteristic is its high refractive index, which gives it exceptional brilliance. Even more impressive is its "fire"—the dispersion of light into spectral colors—which rivals that of diamond. Colorless Zircon was a popular diamond simulant in the Victorian era.
History and Lore The etymology of "Zircon" is debated; it may come from the Arabic zarkun (cinnabar) or the Persian zargun (gold colored). The latter is fitting given the stone's natural variety of colors, including red, orange, yellow, brown, green, and blue. Blue Zircon was particularly favored during the Victorian era.
- Medieval Beliefs: It was thought to induce deep sleep and ward off evil spirits.
- Hindu Tradition: Zircon is one of the nine gems in the navaratna (nine gems). When worn together, these stones are believed to protect the wearer and bring wealth, wisdom, and good health.
Symbolism Zircon is associated with wisdom, prosperity, and good fortune. It is believed to help with spiritual grounding and mental clarity.
Care and Cleaning Zircon is susceptible to fracturing due to its brittleness. It should be protected from hard knocks. Cleaning is safe with warm soapy water and a soft brush, but avoid ultrasonic and steam cleaners.
Tanzanite: The Modern Marvel
Tanzanite is the newest addition to the December family, a gem that has captivated the jewelry world with its unique color and singular origin.
Geological Formation and Sources Tanzanite is the blue/purple variety of the mineral zoisite. It is found in only one location on Earth: the Merelani Hills of Northern Tanzania, near Mount Kilimanjaro. This extreme rarity—being mined in a single, small geographic area—is the primary driver of its value. The gem is often treated with heat to enhance its blue color, a process that is considered permanent and stable.
Gemological Properties Tanzanite has a Mohs hardness of 6 to 7. It is softer than Topaz and Quartz, making it somewhat delicate for rings intended for daily wear. Its most striking gemological feature is pleochroism—the ability to display different colors when viewed from different angles. In Tanzanite’s case, this manifests as blue, violet, and burgundy hues.
History and Lore Discovered in the mid-20th century and popularized by Tiffany & Co. in 1968, Tanzanite has a very short history compared to the other December stones. However, the Maasai people, native to the region where it was found, associated the stone with a life of abundance and good health.
Symbolism Tanzanite represents transformation and new beginnings. It is often linked to spiritual growth and intuition, acting as a trigger for higher consciousness.
Care and Cleaning Tanzanite is sensitive to rapid temperature changes and mechanical shock. It is recommended to set Tanzanite in protective mountings, such as bezels, especially for rings. Cleaning should be done with warm, soapy water. The GIA explicitly advises against using ultrasonic or steam cleaners for Tanzanite.
Blue Topaz: The Cool Blue
While not always listed on the most traditional lists, Blue Topaz has become a staple in the modern jewelry market due to its durability and beautiful color range.
Geological Formation and Sources Topaz is a fluorine aluminum silicate. While Topaz occurs naturally in a variety of colors, the blue variety used in jewelry is almost always the result of irradiation and heat treatment of colorless or pale topaz. Natural blue topaz is extremely rare. Major sources include Sri Lanka, Brazil, Mexico, Nigeria, and the United States (Texas). It is the official state gem of Texas.
Gemological Properties Blue Topaz is the hardest of the December birthstones, with a Mohs hardness of 8. This makes it exceptionally durable and suitable for everyday wear, including rings and bracelets. It is available in three primary shades of blue: Sky Blue (a light, airy blue), Swiss Blue (a bright, vibrant blue), and London Blue (a deep, dark blue).
History and Lore The historical origins of Blue Topaz are obscure. The word "Topaz" is generally derived from the Sanskrit word tapas (fire), or the Greek Topazos. Historically, it was believed to cool boiling water and dispel insomnia and nightmares.
Symbolism Blue Topaz is associated with clarity, communication, and calmness. Its cool blue tones are said to soothe the mind and emotions.
Care and Cleaning Blue Topaz is highly durable and resistant to scratching. It can be cleaned safely with warm soapy water, ultrasonic cleaners, and steam cleaners, making it the most low-maintenance of the four December stones.
Comparative Analysis and Selection Guide
For those deciding between the four stones, specific factors should be weighed:
Durability (Mohs Hardness): 1. Blue Topaz: 8 (Excellent for daily wear) 2. Zircon: 6.5 – 7.5 (Good, but brittle) 3. Tanzanite: 6 – 7 (Fair, requires protective settings) 4. Turquoise: 5 – 6 (Soft, best for occasional wear)
Color Spectrum: * Turquoise: Opaque sky blue to greenish blue. * Zircon: Bright, brilliant blue (often lighter than Tanzanite). * Tanzanite: Rich violet-blue to deep blue (pleochroic). * Blue Topaz: Ranges from pale Sky Blue to deep London Blue.
Value and Rarity: * Most Valuable: Tanzanite (due to single-source rarity). * Moderate Value: High-grade Turquoise and Zircon. * Most Affordable: Blue Topaz (due to abundant supply and treatment availability).
Best Use Cases: * Engagement Rings: Blue Topaz or Zircon are recommended due to hardness. * Pendants/Earrings: Tanzanite and Turquoise are excellent choices as they are less likely to encounter impact. * Statement Pieces: Turquoise offers a unique, organic look; Tanzanite offers a regal, shifting color.
Conclusion
The December birthstones offer a "blue for every personality." From the ancient, opaque protection of Turquoise to the fiery brilliance of Zircon, the transformative violet of Tanzanite, and the durable cool blue of Topaz, the options are vast. While Turquoise and Zircon hold the titles of traditional stones, the additions of Tanzanite and Blue Topaz have expanded the aesthetic and practical choices for the December-born. Understanding the distinct geology, hardness, and lore of each allows for a selection that matches not only personal style but also lifestyle requirements. Whether prioritizing durability for an everyday ring or seeking the rarity of a Tanzanite pendant, December’s gems provide a rich palette of options.