December, the final month of the year, is universally recognized for its festive spirit, marked by holidays like Christmas and New Year's. Beyond the celebrations, it holds a distinct place in the world of gemology, offering a unique array of birthstones that reflect the cool, vibrant hues of winter and the sky. For those born in this celebratory month, a selection of captivating gemstones provides a personal and symbolic connection to their birth period. The traditional birthstones for December are Turquoise, Tanzanite, and Blue Zircon, with Blue Topaz widely recognized as a modern alternative, particularly in the United States. Each of these stones carries its own profound history, geological origin, and set of properties, from the ancient protective talisman of Turquoise to the recently discovered brilliance of Tanzanite. This article delves into the rich tapestry of December's birthstones, exploring their geological formation, gemological characteristics, historical lore, and cultural significance, providing a detailed guide for enthusiasts, collectors, and anyone seeking to understand the gems that define the last month of the year.
Historical Roots and the Journey to Modern Birthstones
The tradition of associating specific gemstones with birth months is not a modern invention but a practice with roots deep in antiquity. The concept can be traced back to ancient civilizations, including those of Egypt, Greece, and Rome, where gemstones were imbued with mystical and healing properties. These early beliefs held that wearing a gemstone corresponding to one's birth month could amplify specific attributes in the wearer's life, such as strength, prosperity, love, wisdom, and protection. This foundational idea evolved over centuries, leading to the formalized birthstone lists used today.
The modern system of birthstones is largely influenced by historical and biblical sources. Many lists are based on the gemstones described in the Bible, such as those on Aaron's breastplate or the foundation stones of the New Jerusalem, which were later arranged into monthly assignments by scholars and jewelers. The American National Association of Jewelers (now Jewelers of America) standardized a list in 1912, which has been periodically updated, solidifying the association of specific stones with each month. For December, this historical evolution resulted in the recognition of Turquoise as the traditional birthstone, with Tanzanite and Blue Zircon added as modern additions, and Blue Topaz gaining prominence as a popular alternative.
The month of December itself is rich with cultural and historical significance. It is a time of celebration, marked by numerous national and international observances. The end of the year brings a sense of reflection and anticipation, themes that are beautifully mirrored in the gemstones chosen for this month. The selection of December's birthstones—each with a distinct color and character—offers a fitting tribute to the diversity and joy of the season, providing a personal touch to jewelry and gifts that celebrate individuality and uniqueness.
The Traditional Trio: Turquoise, Tanzanite, and Blue Zircon
Turquoise: The Ancient Protective Talisman
Among the world's oldest gemstones, Turquoise holds a revered place in human history. Its name, derived from the French "pierre turquoise" meaning "Turkish stone," reflects its trade routes through Turkey to Europe. However, its origins are far older, with significant deposits found in Persia (modern-day Iran) and along the Sinai Peninsula. From these ancient centers, Turquoise was traded across the Mediterranean and into Europe, becoming a staple in jewelry and amulets for millennia.
Turquoise is a hydrous phosphate of copper and aluminum, and its color ranges from sky blue to bluish-green, depending on the presence of iron. The most prized shades are the vibrant "robin's egg" blue, a result of a higher copper content. This stone is relatively soft, with a Mohs hardness of 5 to 6, and has a waxy luster. It is often found in veins within host rock, and its matrix—the web-like patterns of the host material—can be a distinctive feature, particularly in specimens from the American Southwest.
Historically, Turquoise was valued for its perceived protective powers. It was believed to warn its wearer of impending danger or illness by changing color, often becoming pale. This property made it a favored amulet for travelers and warriors. In many cultures, it was also a symbol of friendship and love; gifting Turquoise was thought to preserve relationships. The stone was particularly significant in Tibetan culture, where it was considered a birthstone of fortune, health, and success, and was even used as a form of currency. Native American tribes of the Southwest, including the Navajo, Zuni, and Pueblo, have a deep spiritual connection to Turquoise, associating it with youth, strength, and connection to the earth and sky. Incas and Mayas offered Turquoise to their gods, highlighting its sacred status across the Americas.
Tanzanite: The Gem of a Generation
Tanzanite is a relative newcomer to the gemological world, discovered in 1967 in the Merelani Hills of Tanzania, near Mount Kilimanjaro. Its discovery was so significant that it is often called "the gemstone of a generation," as its sole source is a single, small mining area. This exclusivity adds to its allure and value. Tanzanite is a variety of the mineral zoisite, and its striking blue-to-violet hue is a result of trace amounts of vanadium and heat treatment, which is almost always applied to enhance its color.
The gemstone's color is its most defining feature, ranging from a pure, ultramarine blue to a rich violet-blue. It is trichroic, meaning it displays three different colors—blue, violet, and burgundy—depending on the viewing angle, a property that makes cutting it a specialized skill. Tanzanite has a Mohs hardness of 6.5 to 7, making it suitable for jewelry but requiring care to avoid scratches. Its refractive index and other gemological properties are well-documented, placing it firmly within the beryl family of gems, though it is not a beryl.
The cultural significance of Tanzanite is largely modern, tied to its recent discovery and the efforts of major jewelry marketers to position it as a December birthstone. While it lacks the ancient lore of Turquoise, it has quickly accumulated its own symbolism, often associated with transformation, intuition, and a connection to the spiritual realm. Its unique color and origin story make it a favorite for contemporary jewelry designs, particularly for those seeking a birthstone with a modern pedigree and a breathtaking visual impact.
Blue Zircon: The Brilliant Diamond Imitator
Blue Zircon is one of the traditional December birthstones, valued for its exceptional brilliance and fire, which can rival that of diamond. Zircon is one of the oldest minerals on Earth, with some specimens dating back over 4 billion years, yet the blue variety is a product of modern gemology. Natural zircon is typically brown or reddish, but heat treatment can produce a stable blue color, which is the form used in jewelry.
The gemological properties of zircon are notable. It has a very high refractive index (2.4 to 2.7), which gives it extraordinary brilliance, and a high dispersion, creating a dazzling fire. However, zircon is brittle and has perfect cleavage in two directions, making it susceptible to chipping during cutting and setting. Its hardness on the Mohs scale is 6.5 to 7.5, but its brittleness requires careful handling. The blue variety can range from a light, sky blue to a deeper, more saturated tone.
While zircon itself is an ancient mineral, the blue variety's association with December is more recent. It was promoted as a birthstone to offer a more affordable, brilliant alternative to diamond. Its symbolism is often linked to wisdom, prosperity, and clarity of thought. Given its geological age, some attribute it with a connection to the ancient past and the stability of the earth. Its brilliance makes it a popular choice for rings and earrings, where it can capture light and draw attention.
The Modern Addition: Blue Topaz
Blue Topaz has emerged as a popular modern birthstone for December, particularly in the United States. Its appeal lies in its vivid blue color, which can range from a pale, almost translucent sky blue to a deep, rich aqua or "London Blue" hue. The name "Topaz" originates from the Greek "Topazios," an ancient name for an island in the Red Sea where the gem was reportedly found. However, it was later determined that the stones from that island were actually Peridot, yet the name endured.
Topaz is a silicate mineral composed of aluminum and fluorine. In its natural state, topaz is often colorless or pale yellow. The vibrant blue color seen in most commercial blue topaz is achieved through irradiation and heat treatment of colorless topaz. This process is standard in the industry and produces stable, permanent colors. The resulting varieties are typically categorized by their shade: * Sky Blue Topaz: A light, aqua blue reminiscent of clear skies. * Swiss Blue Topaz: A brighter, medium light blue with a vibrant tone. * London Blue Topaz: A deep, inky blue that is highly prized for its intensity.
Despite its hardness (8 on the Mohs scale), blue topaz has a glass-like luster and deep cleavage, making it somewhat delicate. It is important to handle it with care to avoid sharp impacts. Blue topaz is believed to bring calmness and peace to its wearer and is associated with loyalty and love. Its affordability and wide range of blue shades make it an accessible and popular choice for December-born individuals seeking a personalized and striking piece of jewelry.
Gemological Properties: A Comparative Overview
Understanding the physical and chemical properties of these gemstones is crucial for their identification, valuation, and care. The following table summarizes key gemological data for the primary December birthstones, based on established gemological standards.
| Gemstone | Mineral Family | Chemical Composition | Mohs Hardness | Key Properties & Notes |
|---|---|---|---|---|
| Turquoise | Phosphate | Hydrous copper aluminum phosphate | 5 - 6 | Often porous; color due to copper. Prone to color change and damage from chemicals, sweat, and sunlight. |
| Tanzanite | Zoisite | Calcium aluminum silicate (with vanadium) | 6.5 - 7 | Trichroic (blue, violet, burgundy). Almost always heat-treated. Requires careful setting due to cleavage. |
| Blue Zircon | Zircon | Zirconium silicate | 6.5 - 7.5 | High refractive index and dispersion (brilliance and fire). Brittle with perfect cleavage; handle with care. |
| Blue Topaz | Topaz | Aluminum silicate with fluorine | 8 | Color almost always from irradiation/heat treatment. Deep cleavage; can be brittle despite high hardness. |
This comparison highlights the diversity within December's birthstone family. While Tanzanite and Blue Zircon share similar hardness ranges, their durability is affected by cleavage. Turquoise, with its lower hardness and porous nature, requires the most diligent care. Blue Topaz, despite its high hardness, is not immune to damage due to its cleavage. These properties directly influence how each stone should be set in jewelry and maintained over time.
Geological Formation and Global Sources
The origins of these gemstones span the globe, from ancient seabeds to recent volcanic activity, each contributing to their unique characteristics.
Turquoise forms in arid regions where acidic, copper-rich groundwater percolates through rocks containing aluminum and phosphorus minerals. This process can take millions of years, creating nodules or veins. Major historical and current sources include: * Iran (Persia): The source of the finest "robin's egg" blue turquoise for millennia. * Sinai Peninsula, Egypt: An ancient source, exploited since 6000 BCE. * Southwestern United States: Particularly Arizona, New Mexico, and Nevada, where turquoise is closely associated with Native American culture. The "Sleeping Beauty" mine in Arizona is famous for its pure, matrix-free blue turquoise. * China: A significant modern producer, with mines in the Hubei province. * Other locations: Afghanistan, Chile, and Australia also have turquoise deposits.
Tanzanite is found exclusively in a small, four-square-kilometer area in the Merelani Hills of northern Tanzania, near the town of Arusha. Its formation is linked to a unique geological event: the metamorphism of limestone by heat from the nearby volcanic activity of Mount Kilimanjaro, which introduced vanadium. This specific combination of conditions is believed to have occurred only once in Earth's history, making tanzanite's location exceptionally rare.
Zircon is a common mineral found in many types of rocks, including igneous, metamorphic, and sedimentary. However, gem-quality blue zircon is sourced from specific deposits. Major sources include: * Cambodia: Known for producing high-quality blue zircon. * Sri Lanka: A traditional source for zircon of various colors. * Myanmar (Burma), Vietnam, and Australia: Also have deposits of gem zircon. The blue color is typically achieved through heat treatment of brown zircon from these locations.
Blue Topaz is not typically mined as a blue stone. The primary sources of the colorless topaz that is treated are: * Brazil: The world's leading producer of topaz, including large, gem-quality crystals. * United States (Texas, Utah): Historically significant sources, though commercial production is now more limited. * Pakistan, Sri Lanka, and Nigeria: Also have deposits of topaz.
The geological diversity of these stones—from the sedimentary deposits of turquoise to the metamorphic origins of tanzanite and the igneous sources of zircon and topaz—underscores the varied processes that create the world's most treasured gems.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, December's birthstones are steeped in symbolism and metaphysical lore, beliefs that have evolved over centuries and across cultures.
Turquoise is perhaps the most symbolically rich of the group. Universally, it has been regarded as a stone of protection, warding off negative energy and harm. Its historical role as a traveler's talisman persists in modern metaphysical beliefs. It is also linked to emotional balance, communication, and creativity. In healing traditions, turquoise is associated with the throat chakra, believed to aid in honest expression and spiritual attunement.
Tanzanite, as a modern stone, has quickly developed its own symbolic meanings. It is often called the "stone of transformation," believed to facilitate spiritual awakening and higher consciousness. Its tri-colored nature is thought to bridge the mind and spirit, promoting intuition and psychic abilities. Some associate it with the throat and third-eye chakras, enhancing communication and insight.
Blue Zircon, with its fiery brilliance, is traditionally linked to prosperity, honor, and purity. It is believed to bring peace and tranquility to the wearer and to enhance one's sense of responsibility and discipline. Some traditions attribute it with the power to aid in sleep and ward off nightmares, making it a stone of restful peace.
Blue Topaz is widely associated with calmness, peace, and clarity. It is considered a stone of communication, said to help articulate thoughts and feelings. Metaphysically, it is linked to the throat chakra and is believed to soothe anger, reduce stress, and promote relaxation and emotional balance. Its calming blue hues are thought to evoke the serenity of the sky and sea.
These symbolic meanings, while not scientifically proven, add a layer of personal significance for those who wear these gems, connecting them to a lineage of cultural beliefs and spiritual practices.
Care and Cleaning
Proper care is essential to maintain the beauty and integrity of any gemstone. The diverse properties of December's birthstones necessitate specific guidelines.
Turquoise: Due to its relative softness and porosity, turquoise requires gentle care. It should be protected from prolonged exposure to sunlight, heat, and chemicals, including cosmetics, perfumes, and household cleaners. Clean it with a soft, dry cloth. Avoid ultrasonic cleaners and steam cleaners, as they can damage the stone and its surface treatments (such as waxing or stabilization, which are common). It is best to remove turquoise jewelry before swimming, bathing, or engaging in physical activities.
Tanzanite: With a Mohs hardness of 6.5 to 7, tanzanite is moderately durable but has perfect cleavage in one direction, making it vulnerable to sharp blows. It is not suitable for daily-wear rings unless set in a protective mounting. Cleaning can be done with warm, soapy water and a soft brush. Avoid ultrasonic and steam cleaners, as vibrations and heat can cause the stone to fracture. Store tanzanite separately to prevent scratches from harder gems.
Blue Zircon: Although zircon has good hardness, its perfect cleavage makes it brittle. It should be handled with care to avoid chipping. Setting it in a protective bezel or halo setting is advisable for rings. Clean it with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and sudden temperature changes, which can stress the stone. Due to its brittleness, it is not ideal for jewelry that will be subject to rough wear.
Blue Topaz: While blue topaz has a high hardness of 8, its deep cleavage means it can be scratched or chipped with a sharp impact. It is generally safe for most jewelry, including rings, but should be worn with care. Clean it with warm, soapy water and a soft brush. Ultrasonic cleaners are generally safe for untreated topaz, but caution is advised for stones that may have fractures or inclusions. Steam cleaning is not recommended. As with all colored gems, avoid exposing it to harsh chemicals and sudden temperature changes.
Conclusion
The birthstones of December—Turquoise, Tanzanite, Blue Zircon, and Blue Topaz—offer a remarkable spectrum of color, history, and meaning. From the ancient, protective talisman of Turquoise, cherished for millennia across continents, to the newly discovered and geologically unique Tanzanite, each stone tells a story of the earth's processes and human culture. The brilliant fire of Blue Zircon provides a dazzling link to our planet's ancient past, while the accessible and serene hues of Blue Topaz offer a modern, calming alternative. Together, they encapsulate the festive and reflective spirit of the year's final month. Understanding their origins, properties, and lore allows individuals born in December to connect more deeply with their birthstone, whether chosen for its beauty, its symbolic power, or its personal significance. These gems are more than mere adornments; they are tangible pieces of the natural world, each with a legacy that continues to captivate and inspire.